Pretty much everything you said. The check points have to be planned and signed off on in advance. They don't have to pull every car but do have to have the way cars are selected in the plan. (Like every 3rd car).
VDOT uses the same system at the Ferry (Don't tell anyone, it's National Security
)
Every morning VDOT writes a number down for the Guards and they pull every car that hits that number.
I agree 100% about the TSA. I haven't heard of any VIPER units in Virginia but it's only a matter of time.
They are the biggest threat to freedom in this country in existence.
I see they've asked Congress to allow them to handle ALL mass transit now.