As far as the drug testing goes I do not believe that we should make any mandatory screening. If you suspect that an instructor is using drugs or is unqualified in any way seek out another instructor. Stop into the shop a few times and talk to the instructor to get a feel of the instructor, even talk to some present or past students to help figure out if the instructor is any good. As far as a background check. If you want a background check on an instructor that is going to teach you or your child go pay for one to be done. If you are worried that he/she might be a child molester check your local sex offender registry. Better yet do like I did when I had my minor child Scuba certified, Get to know the instructor, show up and sit in on the classes and training dives.