In some states, like Alabama, Georgia, and Florida, a 'no guns sign' does not mean anything. You can walk past any kind of 'no guns' sign and not worry about being fined as long as you have a license/permit.
In Tennessee, we can be fined FIVE HUNDRED DOLLARS (though no one ever has, you are usually asked to leave if 'found out'), over a stupid sign. It is a Class B Misdemeanor fine only for those with a permit. It is Class C Misdemeanor (lower level) for someone to carry a loaded pistol in their car WITHOUT a permit!!!! It is an A Misdemeanor for carrying without a permit in a public place. What a total joke to be treated about like someone without a permit when I've paid my dues over a SIGN!
Some folks don't feel the need to carry a gun and that is ok. Some folks like jewelers, pharmacists, doctors, businesmen, etc. do carry guns on them when conducting business. To leave a handgun in a car in Memphis, TN instead of keeping it on you is foolish anywhere whether you are walking in a mall or a bank. It's not the inside of the bank that is the problem, it is the walking to and from while carrying money. Sometimes you can't use a drive up window. If you've never been to Memphis, then you don't understand why some folks who are businessmen would actually want to keep a gun on them all the time when in the city limits because it is one of the most violent cities in the country.