Thomas Shey
Legend
Blue's not the only one. I flat out reject the axiom of "One person leaves it's no longer the same game."
But Same GM, same Setting, same rules: May or may not be the same game. Depends upon the characters and the story continuity.
In fact, I'll argue that once you get away from pretty freeform sandbox type things, it doesn't take many players and/or characters to change to complexion of most campaigns significantly, sometimes to the degree there's no longer any point in continuing. Not all campaigns have characters that are just interchangeable cogs.
I make it clear to most of my players that, if you aren't there, your character still is and gets used with or without you.
To a limited degree, so do I; but even among the people I play with there's a difference between that and "your PC belongs to the group as a whole". And there are absolutely people, and its not uncommon, that would find even my "If you miss a session sometimes someone else will just play your character" absolutely unacceptable.
So, no, characters aren't personal property in the same way as dice, nor as book characters: your ownership only matters while you are present. And, for regulars, who gets to play your character when you're absent if it's prearranged.
Also, in some games, given the way the character creation works, you don't even have full control over the nature... Spirit of the Century being the clearest. 2 of your 5 aspects are created by other players.
I think the difference there, as with a lot of things, is people buying in up-front on that (same thing with things like the Shadow in Wraith). That sets expectations. But that doesn't mean one can reasonably expect everyone to be okay with such things, and taking it as a given they will is not a good plan.