I like this idea.
If my flag falls in OTB the game is over. I'd like that option here - plus, if it's in the hands of an automatic process, there's no guilt assigned or assumed with the timeout process.
I'd add another requirement before this goes in. I'd like the option to grant your opponent extra timebank on mutual agreement. Someone goes on vacation, you can give them an extra 7days (or whatever) in their bank and not worry about the auto-flag kicking them while they're gone.