I have no words for that one...
I'ts just soo stupid.... I mean, whatever he decides to do on a bike passanger should know and be ready for it.... that's a basic rule... you would not want them to lean the other way for ex....
He is lucky if nothing happens to that passanger....If she gets killed , or severly injured while he was riding he might be paying alot of money. And for what !!! a stupid wheelie .. to look good...or prove whatever...
If I have passanger, I ride nice... so they want to sit behind you again.... not to scare them sh*less....
Any ways I don't like passanger ppl as you are responsible for them and anything goes down you will be the on paying.