That is a great point. I would like to look and see that just as you would. After running two back to back tournament this year and posting those entries ahead of time, i will tell you why clubs do not do this. Once parents and coaches find out who is in their childrens brackets the club hosting the tournament will get about 25% to 50% of the entries wanting to change weight classes. This is due to running and hiding from other kids or some want more of a challange and want to wrestle the better brackets. Either way it creates a lot of extra work for the hosting club.
