Wouldn't the good etiquette be that if you are exiting and someone appears behind you, you'd try to pull aside and let the team by somewhat right away? Exiting teams first and they obviously are exiting "more" than you are :D
Personally, I would do this going in as well, as soon as possible - as they weren't there before and now they are, it obviously means someone is going faster than me and I don't like stalkers.

