depends
we have had several delivery drivers who have had more serious accidents, and two have tested positive. one even had some extra goodies in his lunch box. its a bad idea to try and get into a wrecked package car in front of the cops, and try and dump some stuff out when you think no one is looking.
as has been said, it is a hit and miss thing in most places. but if it is serious enough, they do have that right.
d