Just how employers require a drug test

I know of a few of companies that have quit drug testing since they were losing too many good employees to failed drug tests; when you struggle to find qualified workers that show up to work and do a good job you don't go and fire them just because of their weekend hobby that happens to show up on a drug test.  You do realize that most employers requiring a drug test do so because in order to be awarded a state or federal contract the company must test their employees for drugs.