Until you have evidence that your children have an actual drug addiction, you should NEVER do what youre thinking about doing. First of all, if they are good kids, leave them be. Secondly, you lose any sort of bond or trust you have with them. If they trust you they will tell you if they have a problem. Thirdly, despite the media, there is no "rampant" drug problem with kids today. The kids are still doing the same stuff they did when I was in school(20-25 yrs ago) They usually stick to drinking, smoking cigs, and pot. Occasionally it gets worse, (crack, meth, coke, heroin), but thats an exception, rather than the rule. Usually kids who get hooked on something have another underlying issue that drove them to go overboard. My advice would be to watch, be open minded, and trusting. If you notice a problem, talk to them. Leave the policing to the police.