I used a PHP sign up system for OP CT2 - big deal. It doesn't mean that a player will attend regardless of posting, sign up or otherwise.
Face it - Airsoft is volutary, not conscription. If you plan a big game and dump a lot of resouces into it - make players prepay - $25 in advance, $35~40 at the gate. No refunds if you don't show up. Parks Ontario did the same thing after getting screwed by their own retal policies. Otherwise you as the game organizer/administrator will be the one left hanging. The reality is that a lot who sign up do not feel obliged to show up as there's no reprocussion.
I admit that I myself have often signed up for games only to bail at some point, for many reasons. I have no problem paying a field fee even if I don't show up.
I see a need to start drawing the line between the casualness of show up and shoot games to actual games that have more planned than just who's showing up and who's not. It's contribution from everyone, not just the game host.