There's sort of an orientation the first day which is good for first-timers.
I usually come a couple of days early to get a better choice of spots. Then I leave a little early. Veteran RTR-ers often start drifting away the last few days since they aren't there for the seminars anymore. They come for the social aspect and once that need is satisfied they head out. Other people leave early because they're dissatisfied with the experience in some way. So between early arrivals, late arrivals, early leavers, people who pop in and out several times, and those going for supplies there's a lot of coming and going.