Granted, I have 0 time "in country." That said, while I can understand being anal with unholstered weapons, and rightfully so, you gotta draw the line somewhere.
The rule at glow-belt central, where I was and Bubba is going, is that horizontal holsters were OK as long as you removed the magazine from a weapon.
Honestly, I didn't see the difference between wearing the magazine on a clippy pouch on the outside of the holster and having the magazine in, but holstered in a way that the trigger was covered and no round in the chamber. I always assumed the "cover nothing with your muzzle that you do not intent to destroy" rule to apply to an unholstered weapon only - i.e. one that you are holding.
But maybe I am wrong. I am definitely not a gun person back in the world - I do not own, carry, etc. Only when I am "downrange", so maybe I am missing some things.