As a former "meatgazer" that had to observe UAs for my armor company, I can tell you that it's true you're subject to a UA at any time at all. I got calls at 3:00 AM to come in. It's a dice toss though if you blaze. They don't test all of the samples, but they do a random cross section of the unit. My company commander's driver got caught twice when he peed hot. They didn't toss him out the first two times, but the third time, they chaptered him out. They put him in the drug recovery program, so after he got caught the first time, the spotlight was on him. So it's not zero tolerance in all units, and this was an active-duty unit, but it's subject somewhat to the commander's judgment. I do know that if it were a "harder" drug like heroin, cocaine, etc, he would've been booted most likely. You need to be super careful if you're going to smoke while in the service. Be sure you have a well-laid plan on how you're going to get that fake urine into that little plastic bottle.