Pilotwolf,
In the US controllers are not enforcers of the rules. If we have problems with a vechicle driver, we contact the airport authority who promptly tracks down the individual driver. I've seen vechicle drivers be fined anywhere from $100 to $1,000 US and/or had their airfield license revolked for incursions, so most vechicle operators are careful because none of them want to be fined or loose their jobs.
Mike
NATCA FWA