FYI, New York and California shop owners can bear arm legally. Different states have different gun laws. The differences are the type of weapons available and background check requirements. Some states have no limits on weapons or background check with easy access to all weapons. Some have 30 days waiting period for background check and ammunition limits.
In california, owner can keep firearm in place of business. New law in CA., more than one person steal or grab stuffs from store, automatically a felony. If you rob a person regardless of amount, it is a felony.