Yes, it should work. I've heard plenty of success stories of DL-flyers who used their FO status to get Air Tran Elite Status during a matching promotion last year. Since there is only one Air Tran Elite level, these members may use the premium security lines in ATL. Delta flyers will flash their Air Tran elite card while flying on a DL ticket, and get right through the security line.

Of course, we've all met some "interesting" TSA agents, so anything is possible.