Anyone can who is on drugs/tobacco can find a way to cheat the test.
All a urine test busts is potheads, so admittedly the really dangerous drug users get a free pass at places that only do that. The potheads thought for a while they could go get this stuff that you drink with about 2 gallons of water and that would beat the test. Now that test comes back as a "blocked" or "diluted sample" meaning the people giving the test know you were cheating. At best you get asked back to give another sample, at some companies they fire you on the spot.
Urine samples are checked for temperature, I hear that is what KROC does for a living, only he tests them by drinking. This makes it difficult to use someone else's urine. They also check horemones to make sure a guy is not using his wife's urine or something.
Where my girlfriend works they test hair. That test is pretty much impossible to beat. Oh and for people with no hair, they take a sample of your fingernail, that will indicate anything you have taken in the past month or two.
The best way to avoid getting busted by these tests: stop doing illegal things.
I know many companies that are trying to regulate smoking out of their employees lives. USAA
has instituted a no smoking policy anywhere on their property. This probably has all 5 Americans left working for that company investing heavily in nicoderm because they have a pretty massive campus so a smoke break could take easily over an hour.
I do not smoke, but in the past at companies I had worked for I would take smoke breaks with the smokers. I would just go outside and stand around with them. I hated the idea that they were getting extra screw off time for killing themselves slowly. Companies are starting to get sick of the lost productivity smoke breaks are costing them. Expect to see more of this. If you do not like a particular company's policies you have a very simple solution: Work somewhere else.
Things were better when it was two guys in a dorm room.