I have the habit in my personal vehicles of setting the parking brake, shifting to neutral to see if it is holding before putting it in park. I strongly dislike the hard pop of the parking pawl being yanked out of its slot when it is disengaged under load. Most of my stuff parks on a slight incline as well.
Folks can NOT follow simple rules. In group runs with new folks that are unfamiliar with the area, the simplest way to keep everyone together is follow one simple rule. If you can't see the rig behind you in the rearview, stop. That ripple effect will go all the way to the leader and save lots of time looking for folks.
I've explained that on every trail run I've lead with new folks who may not be able to find their way back to camp. When I get back to camp and there are only 2 rig behind me, that last guy gets to turn around and go back and lead the lost folks in.
From my days of motorcycle riding “ you are responsible for the guy behind you”