You're both wrong :)
There's no magic 100 day auto boot. There's an abandoned games system that will eventually force the game to finish, though. So it won't remain on your list forever. You can read about it here: http://wiki.warlight.net/index.php/Abandoned_games
It bases its booting off of how long the player has moved in a game, not how long their profile shows them as active for. So it's possible for an inactive player to be in a game if they were inactive before that game was created.