Well, to start off, please let me throw out a few reasons we have to turn people away. Any other staff can jump in at any time:
1. Most of you should see this one coming, but a big reason is fire codes. While it's difficult to estimate the capacity for a single huge hotel, each room has maximum capacity, and if we ever have to start asking people to leave major areas just to meet fire codes, then we are obviously approaching our limit.
2. When people are forced out of an area due to being overfull, they are going to be pissed. If we accept money from new people entering at the door, only to make the new arrivals and the ones already there both unhappy, well, that pretty much screws up our con. Better a wasted trip than wasted money, right? (Note that that last sentence is only referring to people who lived within commuting distance)
3. We always have next year in mind. Having high attendance but subsequently low con quality will give us more money this year, but lose us our reputation, which is important not only to you the con-goers, but also to our relationship with the hotel industry and the nearby community.
Having said all that, the attendance at KumoriCon this year was HUGE!!!!!111 I literally stood there staring wide-eyed for a good 30 seconds when I heard how many people we had to turn away. 8O
Yes, I feel bad about people having to turn around and go home, but unfortunately it always happens to some people at every con. That's why we have pre-reg... we have to. Still, I know turning away 4 people from the Karaoke Contest was hard enough, so turning away hundreds at the door is simply hard to fathom. At least we could guarantee some of them first shot at the next day of the con....