Police mention the following behavioural traits as indicators that someone is armed. Things like:
- frequently touching the firearm for reassurance,
- adjusting the weapon for comfort, or because it has moved out of place,
- an unusual walk or gait, and
- blading their weapon side away from you, similar to the “interview stance.”
The thing is that the property owner has every right to preclude people from carrying weapons onto their property. You have the right to know since that can bring you legal liability as the property owner in some jurisdictions. You are well within your right as a property owner to exclude someone from bringing a firearm onto your property without your permission.
Of course, think if every body called the cops because they suspected someone was carrying on their property--you get the idea why this idiotic idea has been allowed to flourish.
In fact, it's rude for someone to carry a concealed handgun onto another's property, whether a business or personal residence. After all, how do they feel if someone brings a gun onto their property? Especially if the person carrying may have unlawful intent.
I should add that it is probably more frightening to these people that they could be spotted "packing heat" since they like to believe they are inconspicuous. It's probably more frightening and disconcerting to them than having someone grab their gun from them.
Nothing would bother them more than the question "do you have a handgun on you?"