It makes sense. It is Join In Progress. It works best when fewer people quit out (less chance of multiple host changes). JIP is largely the tool that should have been put in alongside a system that discouraged quitting. With a quit ban, people are less likely to quit (as opposed to no penalty at all which meant anyone could uit without any conseqences).
With the possibility of a quit ban looming, I'd imagine people would be less likely to quit in the later stages of a game. Either take the loss or risk getting the ban which would put you out of the game for even longer.
I will note, though, that without players actually being fully aware of the Banhammer, the system will just cause frustration.