It could very well be that they were allowed to turn around. But I bet no one did, because how would they know that this was some sort of volunteer anonymous survey checkpoint until they were right on it? I guess they could have had signs up down the road or something.
“I’ve done it a number of times when I’ve been in a hurry and nothing has happened.”
Did it cross your mind that it might have been a checkpoint to find a fugitive? I have went through two of these, and it didn’t seem like that would have been a wise move.
Freegards
Aren't those heavily manned, equipped and armed? Are roadblocks for fugitives legal?