Been reading this thread to see how the race went - congrats to everyone btw! - and a few thoughts. First, it sounds like this race was oversold. And I don't think saying "well...Disney races are for fun, don't worry about a PR" is an excuse either. My dad has set many a PR during marathon weekend in Disney back in the day, and when I ran this year in 2011 (started in the front/middle of B) the race had plenty of course entertainment, there were plenty of new runners that felt very welcome...yet I had enough room to run my own race.
Re: corral placement - If you submit your time and seed your self honestly, and end up with a slower race, it is what it is. Some days are not just not your day, and it can be hard to tell until you start running what your going to end up doing. But purposely lying to get into a higher corral I think is not acceptable - and as a broader lesson outside of running, what kind of lesson does that pass on to your kids? That lying and putting your own selfish needs above the great good is ok? Not cool.
Re: training. Running is a very individual sport. One can go nuts trying to compare themselves to others. Unfortunately, one cannot change their genetics and natural ability. But, what you can do, is change your training. If you worry about those who don't train as hard as you do (especially if they end up beating you) - you can go nuts. Trust me...been there, done that
Just be proud of the work you put in, and what you can accomplish! Besides, let's be honest - at the end of the day, this is supposed to be fun, and I don't think any of us are planning to make a career out of being a professional runner