Originally Posted by Often1

How would you know whether there's an LEO at the checkpoint? Not all LEO's wear a uniform. More importantly, just like non-LEO private security, a TSO can certainly hold you for a LEO.

Seriously though, the reasons the courts have upheld searches of people who back out (same with U-turns before DUI checkpoints) is pretty obvious.

But, them with $11K+ in their pockets to burn on pranks are free to try.@:-)