Guys, based on the design I've come up with there is no need for a blacklist. Also the occasional no-show if you go to enough games won't significantly penalize you, but chronics will become obvious.
I would keep the system restricted to attendance, that way, its totally objective. Missing a game because your pet giraffe died is still missing a commitment. Nobody is interested in why. Perhaps if you miss a lot of games because you have a lot of pet giraffes and there is an infection on the loose in your backyard pen, you should consider not committing to a game during the outbreak.
Excuses are like assholes, everyone has one.