Well, crap.

Our plans to use the 4 round-trip AirTran tickets for a family trip to Seattle to celebrate my graduation and Lucy's have perished in flames. AirTran apparently has secret blackout dates nobody can look up (in addition to the regular blackout dates everyone can look up) on which you're not allowed to use free tickets. Thus, if you gave up your seat and got some free tickets, the only way to find out when/where you can use them is to get on the phone to Customer No-Service and ask, "How about Seattle between June 17 and July 5? How about X city, Y date? How about Z city, W date?" until you finally get sick of the whole process or die of old age on hold.

No doubt this is why they can afford to be so "generous" to people who give up their seats.