What's the opposite of range etiquette?

I saw a guy who claimed to be a retired Army serviceman and rangemaster not once, but TWICE engage another gunsman currently shooting while still on the "safe" side of the table. The guy was completely oblivious and for some reason the guy who literally must have pointed a gun in the wrong direction a MILLION times before just thought it was fine to approach him without making sure his sidearm was still holstered.