Driving in Gun free zones

I took a friend to visit a relative in a medical institution last week but noticed when driving in that the entire property has a strict no weapons policy. I do carry and have a cpl but was wondering what would happen in the event of a traffic stop or any confrontation with authorities on the property. I never entered the actual building, I just dropped them off and returned later to pick them up but never left my vehicle. Just curious on this one.