Hmmmm... That would be the easiest way, and you're right, they
should always set the E-brake.
Unfortuantely, I have little faith in the realities of training some of the volunteer drivers. Once they get tired of yelling at me that the vehicular repeater doesn't work, because they forgot to set the brake, I'll have to try and retrain them.
Once I succeed, I'll probably have the Fleet Manager breathing down my neck because they've started driving to the E.R. with the E-brake (and the repeater) still on. (Yes, it has happened before. Multiple times.)
So, I'm probably still looking for a "park" sense, although the E-brake has the makings of a good plan"B"
Thanks!

Amateurs train until they can do it right. Professionals train until they cannot do it wrong.