Depending on how long he stays in Amsterdam and stays off of the Cannabis, as soon as he is back in either the US or Canada, and is under suspicion, they can request a urine sample and with Cannabis.....
Joey Stoner flies to Amsterdam, land of legal dope. He proceeds, while on vacation, to get stoned off his arse on the various (illegal in the US but NOT in Amsterdam) recrational substances available. He has a jolly time on holiday, with no incidents, and returns to the US sober, and not in possession of any of the substances he imbibed.
Now while Joey was in Amsterdam, Fred MIBagent photographs him smoking the dope/imbibing the substances...
When Joey arrives back in the US he is questioned. Joey freely admits he got stoned off his arse, and very willingly allows a search which proves fruitless because Joey's not stupid.
Joey is perfectly legal. He has broken no laws in Amsterdam, and the US laws didn't take priority since he wasn't in the US.
....so even if he abstained for a couple of days prior to returning, just hanging out at these cafes or coffee houses gives second hand smoke a whole new meaning.... :cool:
Marijuana is also the drug that is more likely to stay in your system for days, weeks, or even an entire month after the last time that you smoke. Therefore, even though marijuana is one of the least harmful drugs out there, it is also the most likely drug to cause you to fail a drug test.