This topic has pretty much been handled, I think, but having caught this last night on my phone I just wanted to touch on one specific part:
tmagann:
Yes, I realize that a GM might like to preserve the character, but shift it to NPC automatically when the player opts out, and everyone is happy. And old games wills stay out of current lists.
I don't want players disappearing from my game without so much as a by-your-leave, but that bolded segment would make it
especially detrimental. I find, in my experience, that players treat characters with an NPC tag far, far worse than they treat their fellow PCs (despite the fact that the only difference in them is who is controlling them). In a lot of cases, it's more beneficial to have an abandoned character remain a PC, controlled by either the GM or another player (perhaps while being shopped around for a replacement player) than to immediately have them move to the bottom of the list and pick up an NPC tag that is like a big neon sign (apparently) that 99% of the players no longer have to pay attention to it.
If -
IF - there was ever an option for players to leave a game on their own (and thank goodness there isn't), it would need to be as covert and non-obvious as possible, IMO. It's just not good for the running or the morale of a game, otherwise.