FormerlyHemlock
Hero
More personally, in sports, a benched player worth a ---- doesn't take off because he/she didn't get to play, or because they can't play -- they stay for the team to the end of the match, because they're a team. To me, that says as much about character as taking off because you got sidelined does.
It's interesting people keep mentioning sports.
In fencing, once you're eliminated from the tournament, it's considered non-mandatory but courteous to stick around for at least a while and root for your friends and other fellow fencers who are still in the tournament. If you get eliminated early on, you're not necessarily expected to stick around for the finals several hours later, but if you had a close friend and they ended up winning the tournament, and you had left right after you were eliminated and were at home watching a movie the whole time they were fencing, you might feel at least a little chagrined.
I mention this only to say that different sports have different expectations. D&D doesn't necessarily have to be like fencing.
I will say that if a player does choose to stick around after being eliminated from a game session, it is rude if the DM doesn't take the player's feelings into account. GM4P said his DM explicitly denied him opportunities to run monsters, make a new PC, or even talk to the other players. I call that bad form on the DM's part. I don't think GM4P was necessarily obligated to stick around, but it should have been made possible for him to do so and still have fun. That's what I try to do for my players and I hope I succeed.