(hint to thieves - look for the outlet with the grounding plug on the top!)
I actually install all plugs with the ground on the top.
There is no reason but convention as to which way to put which side up. But, if in say, a workshop you had a conductive piece of material slide down a cord or slide down the wall to the plug contacts you would get a short unless the ground was up. I have poised that scenario to a few electricians who adopted the thinking (at least in shops).
I used to have one of those safes in an old house. You also have to sharpie inside the holes because they don't go deep enough to cause any shadowing.