In several more tweets, she indicated she was clearly unhappy, calling the Hilton first "arseholes" and "cheap bastards" and saying she hoped her tweets deterred others from staying there.
Later, she said the family had decided to pay for internet access, but refused to eat in the hotel or spend anything extra, and would avoid the chain in future.
"Also, now we've paid were downloading heaps," she wrote.
Carnahan Darby isn't the first guest to complain about the Hilton's internet policy - TripAdvisor is full of posts such as "Hilton's Wi-Fi policy sucks" - alongside similar complaints about other luxury hotels, which can charge up to $20 per night to access "premium" internet speeds.
Many only allow members or those who book direct to access Wi-Fi for free.
The policies are in direct contrast to those employed by cheap hotels and backpackers, where Wi-Fi usually comes at no cost.
Despite surveys revealing the behaviour infuriates customers - in fact it is at the top of many travellers' must-have lists - many hotel chains have been slow to change.
Some critics say it's to keep fast internet as a perk for loyal customers only, or to do with the challenge of maintaining premium bandwidth speeds. Others believe it's to encourage guests to watch pay-per-view instead of Netflix, with the hotel clipping the ticket on the way past.
Tony Repetti, a hotel management professor, told Marketplace.org in 2014 he thought the reason luxury hotels made guests pay was "because they can".
He says, luxury hotels will charge more because they know their customers will pay more.
"A $20 fee on a $400 room ... is probably not a big deal when they're paying $400 for a room," Repetti said.
The only way to change the behaviour, the experts agreed, was to vote with your wallet.
As for the Darbys, they look like they'll be doing just that - Carnahan Darby tweeted that next week, she'll be trying the Sheraton instead.
