The total amount of extra effort required when setting any weapon down to make sure where the business end is pointed is so minimal as to be zero. When that extra consideration is weighed against all possible outcomes (forget Murphy's law) it should become part of normal firearm handling, just like always checking the action/chamber of any firearm you pick up.
I'm sure things are seen somewhat differently in a combat zone however and will give the professional soldier a great deal of leeway when it comes to these matters. But I have seen in numerous videos where they seem so careless with where the muzzles are pointed, it just gives me the creeps is all.
