gtrdone, if you were to put me out by the gate to act as "compliance officer", instead of running back to you with my list of "bad boys" to be spanked on the wrist that day, I would probably tell ecah one the make sure that the lock is properly latched. That there is a push for compliance.
If the pattern is set and the habit is established then locking the lock becomes second nature. The same is true about driving habits. Set the pattern from the beginning.
:USA:
I would not ask you to run tell on anyone.. I would ask you to find out what trailers did not have locks, what locks did not work properly and communicate it back to me so the problem would be resolved!