I would doubt that a school will let us put all that water on their hard wood floor. It would be nice to have that area but the probability of the floor getting damaged is just too high. Its not a question of if the floow will get wet, but how much water will end up on the floor from spilled/punctured bags, water dripping off hands fresh out of a tank, or god forbid a tank turned over.
The last Denver swap (not the one this weekend) was in the basement of a church. Nice facility, but a PITA to carry all the stuff down stairs and them back up at the end of the day. Cleveland used to hold their swap at various Hotels in their confence rooms. Nice because people traviling long distances can stay there before the swap. Down side is they may not be geared for all the power consumption in one room. The last swaps were at Party Centers. there was plenty of space and parking plus the power was all dedicated to the swap.