Those customers can deal. I once got punched out by a customer at a Preston’s Milk Store in San Angelo, TX, because I had to ask him for ID as part of a zero-tolerance policy the local cops were doing to crack down on underage drinking. As a result, I have never complained whenever anyone’s asked me for ID.
The time will come when it would make your day if someone would ask to see your ID. Once or twice I’ve even been reduced to asking the clerk, with a grin, "Don’t you want to see MY ID?".