To add a postscript to my original post: we made our 11:45 a.m. flight out of Houston with NO problem. First of all, Royal Caribbean has an option for early departure off the ship if you're willing to cart your own bags off. No problem. We were told to be ready by 7:00 a.m., and around 7:05 a.m. about 100-200 of us were walking off the ship. After a quick walk through customs/immigration, we were outside to catch our transportation by 7:30. A cakewalk. And of course, Sunday morning freeway traffic was light, so we were at Bush Airport by 8:30.
Taking off your own bags -- and not battling everyone at the dock trying to find their stuff -- was very cool. I'll do it next time I sail on Royal Caribbean.