Sacred Haven of Debauchery

Well, in IRL parties (if I understand the idea correctly), no one waits for anyone. If a person doesn't show up at the agreed-upon time, their character simply doesn't participate at that moment, and that's it. If the GM wants, they can compensate for it later somehow, perhaps by considering missing a day as a "loss of levels," but I'm not even sure if it's worth going to such lengths.