I'm just curious. What exactly is the big deal with no-shows. For these massive clusterfuck "big OPs" -- can't you just guesstimate how many people will show up to a game and how many will flake out? For me, this has been easy. There has only been a couple times when I've either been in trouble of financial loss or had to seriously change game-play because of no-shows. The rest of the time I get a 90% attendance rate and sometimes there's even people who didn't sign up who offset that number.
If we were serious about registration, everyone would pre-pay. Right? But some people don't want a pre-pay system, because they'd be worried that the game may not happen and they might not get their money back. But if they're worried about that then they don't take the game seriously to begin with, so why are we surprised when they don't show up?
So what is the solution? I don't think threatening to ban no-shows or put them on a "naughty list" is the answer. Like everything else, eventually it's going to be dropped or ignored. Exceptions will be made for some people but not others. Drama will ensue. There's got to be a better way.