Unicef Kazakhstan helped them sort out the problem and they were let through, but not before a week of waiting and more than a few expletive moments.
"Mentally I was stressed out to the max," added the 40-year-old Riosa. "We were seven days ahead of schedule and it took us a week to get it sorted. We stood our ground and eventually were able to go into China. I thought of the song Hotel California - 'you can check out any time, but you can never leave'."
Riosa (extroverted and volatile) and Newick (introverted and diplomatic) are poles apart in personality.
The only other "we're not going to make it" moments on the trip that has cost them around $15,000 each came when Riosa experienced bike failure and struggled physically in Turkey.
"The hills were nonstop," said Riosa. "You were either going up or down, going down would have been easier. However, the roads were not the best and in need of repair."
"Nic told me he was thinking of pulling the pin in Almaty because I was hurting him too much on the bike unless I started to look after him more," added Newick.
The roads in Kazakhstan were no better.
"We biked in and out of pot holes for days on end; at times they were more like craters."
Riosa endured bike problems where his carriers broke and were replaced, and he broke many spokes due to the "need of repair" roads.
While the bully of a border guard is the standout bad memory there are many more good ones that have made it all worthwhile. Their tagline is "friendship without borders" and they have met some great people along the Silk Road.
"On our second day in Kazakhstan it was 50 degrees and we ran out of water and Nic just held out his water bottle and every time the car would stop and check on our welfare and gave their water freely," remembered Newick.
"We have been in poor parts of the countries and we have found these people are nice, friendly and are just good people," said Riosa. "A lot of stories we heard from people were just not true. People stopped their cars and wanted photos with us. That was kind of cool."
There is no substitute for experience and the challenge of the Danube River - including Newick suffering from dysentery - meant they were prepared for anything.
"Like most long events we both have our good and bad days however most of the time we know what we have to do and get it done," said Riosa.
This adventure was a completely different challenge to the kayak.
"The Danube we had a support crew carrying all our supplies, shopped for us and so on," said Riosa. "This time we have to carry everything, do everything ourselves and have to rely on each other to make it through each day."
"Cycle touring is easier because you can fix problems before they get on top of you like having a sore bottom all you have to do on a bike is stand on the pedals," said Newick. "Where in the Danube it would mean paddling 200-400m into a mosquito plagued forest and pulling yourself up off the seat, all the time hugging a slippery tree trunk."
In 2012, Riosa wants to attempt the Guinness World Record for 24 hour kayaking on moving water which is now 432km on the Yukon River.
"I am looking at a couple of rivers in Siberia and my goal is to try for 500km. This is going to be an expensive challenge and will need to find some funding to do this one and a lot of help on the Russian side."
Newick, who wants to write an inspiring book about the Danube and Silk Road experiences, reckons he will get roped in again.
The adventures of Riosa and Newick will continue.
"If you listen to my niece it's because I am stark raving mad but I prefer to think of it as a spiritual, emotional and physical challenge," said Newick.
"Physical adventure drives me," said Riosa.
"I could be working, but kayaking down the Danube River and then biking from Bucharest to Beijing just sounds better.
"What a story I can tell my kids one day."
Coming up
Today
Winter Games (Penultimate day)
Super G - Able body and Adaptive
Snowboard Half Pipe qualifier
Winter Triathlon
Curling semifinals
Speed Skating day 1
Running & Tramping
Great Naseby Water Race
Central Otago. 50km Solo, 80km Solo, 100km Solo, 60km 2 person teams.
Tomorrow
Running & Tramping
Jerry Clayton BMW North Shore Marathon from Gould Reserve, Takapuna Beach. Options: marathon run, half marathon run/walk, 5km fun run/walk and 2km kids run.
Snow Sports
NZ Biathlon champs, Snow Farm, Cardrona Valley.
Winter Games (Final Day)
Snowboard Halfpipe finals
Curling finals
Speed Skating day 2
Sunday (September 4)
Running & Tramping
Xterra Auckland trail run series event 6 - Hunua Auckland. Course options: Short 5-8km, Mid 10-14km, Long 16-20km, Super long 21km+ short and mid courses can be walked