Glom,
Not a single incident that I am aware of.
As far as the vehicle licencing issue was concerned, the old chestnut of not being able to correctly identify an airfield signal light was always trotted out. Well in over 20 years regular and 4 years reserve service I recall only once having to drive on an airfield and get a clearance to cross a runway. Guess what though, I had a radio with me to talk to the ground controller.