If your purpose is actually to do a hidden city ticket, AA's not likely to hoist you on it unless you do this repeatedly, from the information in this forum we have from other posters. See http://www.flyertalk.com/forum/ameri...aster-thd.html.

As others have mentioned, AA has options: schedule changes, IROPS, they could fly you directly to PHL or have you connect, say via MIA. You have options, too: if the schedule changes significantly (2 hours or more, generally) you can cancel and make alternate arrangements - which might be more expensive. In essence, you're gambling to save some money, it would seem, and there are no guarantees.