quick question for the travelin folk out there...

my homie from Taiwan is visiting.
lets say for whatever reason he gets in trouble when he gets back home and they make him take a pee test. (the gov there makes you take a pee test if you are suspected of using drugs) if he says he was in a medical state like cali, or if he says he was in amsterdamn where smokin is cool, would he still get in trouble for testing positive for some weed?

i know its a long shot, but i figure this is the best place to ask this.
thanks
peace

to be honest i have no clue but if hes from a place that make you take a pee test just cause they suspect your on drugs i dont think there give a fuck if he was in a amsterdamn or not and there still throw the book at him just my .02 cent