A warning to parents traveling on Southwest Air:

Yesterday, my sister checked 3 carseats for her flight. Southwest canceled their flight twice and rebooked them for Wednesday. My sister asked for the carseats back so they could leave, and Southwest refused. 24hrs later, same thing.

Apparently this is Southwest policy - once you check a bag, they won't give it back, even if your flight is canceled and rebooked for another day.