In a tournament a few weeks ago, I was taking lineups behind the plate and getting confused over some specific tourney rules myself regarding substitutions, lineups, etc. Luckily, it was during a pool game, so I had time to get clarification before the bracket play.
It's fun to umpire a whole bunch of different types of FP, but it does get confusing and I find myself having to really concentrate on which specific ruleset I need to use further modified by the By-Laws, tourney's, etc.