Employers now testing all new employees
At least as far as I can tell.
Read a book called Nickel and Dimed - a woman tries to make it in the US on minimum wage just to see if she can and writes about it. According to her, the average company pays about $50,000 drug user when you factor in the cost of negative tests per once in a blue moon positive.
Sign of the times.
Oh, and when I went to HS - they were required to provide advance notice of locker searches (and did several times - searches were to "locate missing library books" but there was generally at least 48 hours notice).
