Forever Offline Characters
If a character is offline for more than about 2 months without vacation mode on, you should hand off all the characters in the games that they were in, that way the hosts/narrators can continue the game. I've had several of these issues, and I'm sure many other people have too.
Better yet, make the period shorter than two months! If people aren't going to participate, the system should filter them out when at all possible.