My suspicion is that it might be slightly more crowded, but with people traveling with friends, unmarried couples and married couples without kids (or without school-aged kids anyway). I would think that time of year, minus the week and change leading up to Labor Day, is very difficult for families with school-aged children to go. Either they're already in school or just about to go, and after Labor Day, every school is in session. Sure, some people might opt to take a vacation near the end of September, but IMHO, even kids who love WDW would realize that would be a bad time to go if they expect to keep up with their school work throughout the course of the year. I mean, going in the winter, you have a better shot of getting back into the flow if your family goes on vacation, but in that first month, if you're not grasping what the teachers are throwing at you, you might not ever catch up. If I were a parent, I'd probably be tempted to take a kid out of school to travel in the off-season, but not that first month of school. Of course, my future wife is a teacher with a strong work ethic, so that's not gonna happen anyway!