So 1% of the U.S. population is good to go with a Mil ID flash. Good for us.
This is what you are failing to understand. The person driving isn't the one holding up traffic. It's the Federal Agent that is the one holding up traffic!
Here's how it should go-
Driver pulls up to checkpoint-
LE: "Sir, are you a U.S. citizen (or have you had anything to drink this evening)?"
Driver: "I respectfully refuse to answer any questions"
Assuming LE has no reasonable suspicion person is illegally in the country or intoxicated at that point, LE then says: "Have a good day, sir."
Driver pulls away from checkpoint.