Why is it so important for employers to become perverted "urine collectors"? For most jobs, it probably wouldn't even matter if someone came to work slightly "impaired. For the rest, unless someone is obviously not "right", it doesn't matter if they are impaired because of chemicals, depression, illness, or lack of sleep. All those things impact performance. I don't want a surgeon cutting on my brain with any of these issues hanging over his head. Why are "drugs" singled out?
Your personal time is just that: personal. What you do on Friday night is not your employer's business on Monday (or a couple weeks later). Liability wouldn't be an issue if we could get back to holding people responsible for their actions and any harm they cause. But then, Congress would all be facing the death penalty, wouldn't they?
Which drugs are OK to use? Ibuprofen? Benedryl? Alcohol? Caffeine? Chocolate? Broccoli? Every single substance you ingest or inhale affects your body chemistry in some way. Some have more of an effect than others, but if you are able to do our job without putting anyone, other than yourself, in increased danger, then you should be left alone, and any bodily fluids you contain should be yours to do with as you see fit. If you apply for a job that demands a urine sample, give them one right then and there. Let them get a sponge if they want to put it in a cup. It is time to stand up like humans with dignity and say a loud "No!" to this sick behavior on the part of government and its worshippers.
Now, I recognize that employers have a right to require just about anything they want. On the other hand, no companies had even thought of this intrusion until it became a government fad. You also have a right to refuse a job if they make ridiculous demands. Without the blessing of government, fewer companies would try to get away with this sanctioned molestation. In a future, free, America there will be enough companies and opportunities competing for your skills that you will be able to pick and choose.