I hope we are not descending into the socialist madhouse of "you can't do anything which isn't required."
Maybe the local stop and rob isn't requesting OC'ers to show licenses. Most of those are one big room, limited product line operations. They get little attention unless there is a problem, like selling beer to minors. Then, there is a problem!
Walmart is not, and the threat of losing all of its licenses, or having them suspended through inadvertence, is a prospect they wish to actively avoid. They are under constant scrutiny, subjected to all manner of set ups, scams and stings by the legions of Walmart haters both goverment and private busybodies. Walmart may have more lawyers handling
phony "slip and fall" incidents than the Attorney General has lawyers working for it.