It could easily get into a game of "I'm not to blame." The GA would say, sorry, you weren't properly screened and I can't let you on the flight. I have to keep up the stats for the flight. If you're not onboard, you don't go. It's not our fault the TSA messed up.

The TSA would rescreen you and send you back, but tell you that they don't compensate you for missing your flight and that you should have gotten to the airport with plenty of time for all contingencies.

In other words, yeah, you could have been hosed.

Mike