When was younger hopping around to different golf courses the supers would usually tell me they don't care what I do on my time, but don't do it on the clock.
Uponone- they do have test to detect the amount of drug in your system at the time. Say you are a weekend pothead and cut yourself with a chainsaw. They will do a GC/MS test to detect the amount of canaboids in your system at the time of the accident. In this example, this guy would be okay and get his bills paid for.
Another guy takes a few hits in the truck and 20 minutes later he cuts himself with a chainsaw. He would not be okay, get fired, and denied medical bills