The point I am making, is that at some stage, let's face it, drug use gets out of control and in my opinion should be taken out of the hands of the user.
Ooohh, that's a pretty broad statement....
I agree with both above posts, but as an amalgamation: drugs shouldn't really be in the workplace. If you're actually using drugs AT work, you probably have an issue and your working situation needs adjusting. But by the same token, drug testing shouldn't be in the workplace either. Judge the worker by their performance.
I knew I had hit a low point in life when I was using stimulants at work (an office job - no heavy machinery, no saving babies, etc) simply because I could not find the motivation to go on otherwise. I kept going in that way for nearly a year before I bailed out (of the job). Nobody ever suspected that I was using anything. Because I was so miserable, the stims merely balanced me out and allowed me to continue doing something I was sick to death of.
There was no drug testing at my work place because there was no need for it, it really was just office work. But myself and a few others had our semi-secret vices simply because of the soul crushing nature of the never-ending 9 to 5 office existence. I've worked with alcoholics who VERY discreetly drank at work. People who not so discreetly smoked joints at work (how they could do that at lunch and carry on competently - which they did - has always been a mystery to me, weed would have <metaphorically> put a big sign on my head reading "I'm a crazy person"), and of course I've worked with stim users from the marketing department who were annoyingly productive and obnoxious in the office.
Don't do drugs at work!! If you do and it's obvious, then it just gives more fuel for the idiots who want to invade everyone's personal privacy and drug test after weekends or holidays. Be upstanding and reliable at work, then it shouldn't be an issue what you do in your own time.
<I know that's not how it is, but I'm stating that's how it should be: work well, be competent, get left alone>