Originally Posted by TravelinWilly
Not really. Last I heard those carriers didn't have 1st/biz., thus they could get away with no assigned seating - there's no place to which one can upgrade.
Re-read the thread -- this was not in response to upgrading. It was in response to TSA not allowing people to swap boarding passes because they wouldn't be able to identify who was in a specific seat.
The TSA (rightly) would not care who is in what seat -- proof: some airlines don't have assigned seats.