At plenty of airports where a two-minute idle or stopping of the car gets the local authorities irked, the routine outcome of such policy/practice is little additional security and quite a bit more gas wasted.

The weird thing used to be these smaller regional airports in rural areas that had National Guard presence and the barricades to keep cars far from the pedestrian side of the terminal but only had scrawny fences and no barricades near the areas where passnegers are most concentrated in the airport. (It wasn't just rural area commercial airports, but also some airports in larger metro areas too.)