If you want to carry a gun in your car carry a gun. Don't advertise that fact.
But lets just say you own a business that has experienced some thefts and wish to search all vehicles at the end of a shift in an attempt to find the culprit(s). During these searches you find an employee with a carry permit has kept their personel protection properly secured in their vehicle during that shift. If that employee has not done anything offensive or unlawful, they should be protected from termination just because their carry beliefs are different than your carry beliefs. It is no different than terminating an employee because you witnessed them entering a place of worship that differs from your place of worship.