Thanks for the replies--AirTran apparently left about 15 people stuck in ATL overnight, as the door closed at 7:32, per some of the other pax who were misconnected, which was 18 minutes before scheduled departure. Of course, their system showed 7:40.

AA did this to me in DFW a month ago, but at least gave us hotel and meal vouchers b/c our connection came in late.

A common-sense policy for all airlines would be to hold the last flight out of the day from a hub for any connecting pax that have a reasonable shot at making it. I never mind waiting myself in these situations--per a FA I talked to about it, the problem is usually the gate agents trying to leave, as the flight crews are always willing to wait.