There is the rub. Is it up to the employee to declare he feels unsafe if he sees an open carrier?
Simple employee training is paramount. A gun in a holster is not a threat. A gun out of a holster may be. A store employee should be fired on the spot if he calls the police on a person open carrying where the gun is always holstered and the person is not acting dangerously. This works for pistols. I don't open carry rifles in stores so I will defer to others for that. I would think that would be a little more challenging. Like rifle slung so that it never muzzles anyone, probably bolt open, and certainly safety on, though an untrained observer would not be able to tell such things.
Personally, I prefer CC in a store or public environment. Open carry seems more appropriate in a outdoor setting, not in crowds, hiking, camping, etc. But that is not to say one shouldn't be able to open carry where its legal.
I see an opportunity here. Walmart, or others, might be ripe for externally provided employee training by qualified experts in safe gun education, safe gun handling, and threat awareness. Would be good if all these snowflake store employees actually got properly introduced to the great equalizer.
“Simple employee training is paramount. A gun in a holster is not a threat. “
That is illogical to people who have been raised to think the very presence of a gun is cause for panic. In their minds it’s guns kill, not people doing the killing.