I have tried such a bike more than once and it is difficult. So far I made about 10 to 15 yards before the bike sabotaged further usage.
http://www.erlebnisbahn-ratzeburg.de/archiv/bilder/pic2scr.pl?file=2006/Falschrad_1024x768.jpg(That picture of from the location's web site, I'm not the person in the photo.)
The guy in the video did have a straight path to follow with lots of empty roome to the left and to the right. In Schmilau, that is where that picture is taken, you don't have the room to really explore that bike.
It is not only that knowledge is not a synonym for understanding, what [probably] everybody is doing wrong in a situation like this, is the simple thing of overreacting. Did you see how far he turned the handlebar und thus the wheel? If you corrected your driving like this with a regular bicycle you also would eratically hop off the bike.
The next time I'm at that location is in October. I will try that bike again. If you have a chance, try such a bicycle. It is quite an experience.