"We think there is a shift," says MediaWorks legal counsel, Clare Bradley. "And that shift could potentially be commercially problematic for us."
But Sundborn and other parents have become increasingly concerned that the shift is in how much adult content is creeping into shows watched by children.
"I definitely think there are more adult themes at earlier times," says Sundborn. "I think back to my own childhood and we used to watch things like Happy Days and Family Ties with wholesome morals. Now a lot of the themes tend to be sexuality, relationships and cheating."
Parents are worried about what their pre-teen children - still up and about doing homework or watching TV during primetime - might unexpectedly see on programmes such as Shortland Street, known to push the boundaries in terms of acceptable, early-evening viewing.
In 2008 the BSA found against the 7pm show for a suggestive gay oral sex scene. And last year it upheld a complaint about violence in an episode, "particularly the insinuation of sexual violence".
Sundborn says broadcasters have a great responsibility to their young audiences, who are hugely influenced by media and model what they see on screen.
"I think soaps like that [Home and Away] set norms. I don't know if they're meant to reflect reality, but if it's not the reality that we have then it will soon become reality."
Whenuapai mother-of-two Justine Boot, 38, is also worried about what her two young daughters might inadvertently see and hear on television and radio. She thinks TV viewing standards have "slipped" in recent years and that a "slightly sleazy" aspect has crept into programmes screened before children are in bed.
Early in the evening, before the news comes on, she is cooking dinner. Tonight, she and her doctor husband Peter will have grilled tandoori chicken with tomato salsa; the girls have already eaten last night's leftover lamb shanks, mashed potato and beans.
Now, they're next door in the lounge, cuddled up on the couch in front of the TV; Lottie the border collie is snoozing on the sheepskin rug by the open fire.
If she allows the children to watch the TVNZ or MediaWorks [TV3 and C4] channels, Boot has no idea what they may see. She can't control it from the kitchen. So she restricts Victoria, 4, and Harriet, 2, to the Disney channel, because she knows they won't see anything that is offensive.
But as they grow out of Mickey Mouse and Bunnytown, as they head off to school, she knows she will come under increasing pressure to allow them to watch other TV programmes.
She is prepared to do battle to restrict what her kids watch if there is any chance "inappropriate" content will be screened. Even Coronation Street has become "raunchy", she says. "I'll walk into the lounge to put another log on the fire, look up and there is some quite raunchy scene or something overtly sexual on Coronation Street. I think, My goodness, how times have changed.'"
TVNZ boss Andy Shaw makes no apologies for the changing times. Shaw, with the heavyweight title of general manager of acquisitions, commissioning and production, argues there is no deliberate attempt by programmers to show increasingly raunchy programmes to prop up ratings. Rather, the way drama is told and shown has changed, he says.
While he concedes some scenes in Shortland Street would have caused an uproar if shown 20 years ago, audience expectations have changed.
"We are living with a generation who have been media savvy for their entire lives and they are used to seeing it and hearing it," he says.
Try storytelling in a way that was acceptable in 1975 and "people just won't watch it", Shaw says. To illustrate his point, Shaw cites American TV censorship rules that at one time demanded that the leading man keep one foot on the floor during a bedroom scene, which then faded to "crashing waves". He says: "The audience won't tolerate that sort of storytelling now. They've grown up."
All that is no consolation to mums and dads whose only choice is to turn off the television after the news rather than risk their kids seeing steamy sex scenes during teatime.
Mum-of-two Gabrielle is among those who switch off the TV rather than jeopardise the innocence of her 8-year-old daughter.
Shortland Street is banned; so is Coronation Street and The Simpsons. The Auckland mum is "appalled" that Outrageous Fortune is screened at 8.30pm - adult-only time or not. She thinks because of its raunchy and violent content, it should not be screened before 9.30pm to ensure pre-teens don't see it.
"It restricts my viewing," she says. "Sometimes I have to go into my bedroom to watch a particular programme and then I'm not sure if my daughter is flicking through the channels and what she's watching."
Like other mothers of young daughters, she worries about a form of "precocious puberty" caused by the bombardment of adult images on television. In other words, a loss of childhood innocence - growing up too fast.
Diane Levy, family counsellor, therapist and grandmother, agrees. She thinks too much sex too soon does increasing damage to children's "sense of self, their sense of modesty and appropriateness".
"I cannot see any benefit whatsoever to our children. The only benefit I can see is to the advertisers."
Levy dismisses as "bunk" the argument that young viewers are simply watching real life. "We aren't watching real life," she says. Major relationship issues cannot be solved in "22 minutes with three ad breaks".
Shaw says parents should know what their children are watching and "set their own boundaries".
He rejects the argument that parents might not be able to do that at 7pm, that they might just want to get on with cooking dinner and helping with homework without worrying whether a sex scene is going to pop up on the TV in the background.
"Obviously I'm the last person to suggest anyone turns the television off. It's free-to-air television broadcast at home. We make our decisions on what we think is appropriate and right."
But, he says, parents have as much responsibility in deciding what young children watch in the early part of the evening as deciding if they can watch The Mentalist or Outrageous Fortune. So he's adamant a show like Shortland Street will not run later, say, at 8pm.
Television is a "business", he says. "I have to have shows that can deliver huge audiences at the best possible time, and Shortland Street has been the linchpin of the TV2 schedule. Where it's scheduled is not up for debate."
Instead, Shaw puts the onus back on parents to decide whether or not their children watch the news - which carries no parental restriction - or programmes screened after that.
"It's not a case of where we say, You don't have to make any judgment call, we'll do it for you.' This is not a nanny state." TVNZ has a very clear understanding of what the BSA finds acceptable and what it does not, Shaw says.
Broadcasters are expected to use their judgment, "and we do," Shaw says. "We are not here to alienate or offend, that is obviously not in our interest. We want audiences to be comfortable watching our programmes, as adults and as families."
Christchurch television researcher Ruth Zanker says at 5.30pm a mother should be fine to "get the veges scrubbed and leave the children with innocent material to view that's not salacious or sexual".
Unless people complain over what they regard as unsuitable content "the temptation is for content to drift to more adult content," she says. "If channels aren't called on pushing the boundaries then they figure it's okay."
Zanker says there are particular concerns about importing overseas shows and screening them in different time zones, such as Home and Away which TV3 screens at 5.30pm in the (G) rating time zone - earlier than it's air time of 7pm in Australia when parental guidance is recommended.
Levy and the mums also worry about the TV promo ads which come on in the middle of family programmes.
Levy says the most "salacious" and "juicy" parts of an upcoming programme, due to be screened later in the evening, are suddenly shown during ad breaks, something she finds "incredibly offensive".
"They are shown completely without context. These are not what I would want my children or my grandchildren to be seeing."
Sarah O'Neill of Waiuku is waiting for a BSA decision on complaints she lodged over promos screened during children's movies. The mother of two children, aged 4 and 6, objected to a promo of the film Cellular showing a child being kidnapped, that was screened during an ad break in the animated movie Ratatouille.
"That's something I don't think children need to see," says O'Neill. Boot says they expect there to be adult content after 8.30pm, but the increase in sexual content in primetime is alarming.
"I think it is far more insidious when it [sexual content] is on a programme like Home and Away or Shortland Street. And kids are going to be watching it."
Boot is equally shocked by some of the adult content she hears on the radio when she is driving Victoria to kindy. Channel surfing to find a song she likes on easy-listening channels, Boot says she is "grossly offended" to hear graphic advertisements for erectile dysfunction or brothels at 8.45am.
So far she hasn't had the "what does that mean" question. "I know I won't be ready for that question for quite some time." Boot says. "I just think there are things that children shouldn't have any knowledge of whatsoever."
She thinks that all adult content, including radio ads, should be restricted to after 8.30pm.
Levy agrees. Enough is enough, and it's time for parents and authorities to step up and rein in the TV channels, if they refuse to do it themselves.
Otherwise, she says: "Parents are forced to become the Luddite who switches the television off and doesn't let their child watch".
