ive seen fake money used many times, hell, certain churches like to use them to give to people instead of tips. waiter thinks its $10/50/100, they pull it out and see "why beg for money when you can pray for forgiveness?" crap on it. only to lose their job for not getting enough tips or some crap like that.

its only illegal if its trying to copy real Legal tender. if you see a brief full of wads of Canadian cash, only to get close and see "Play my gaem! eh?" on it. at least it made you look.