Like this idea, but nix the specific areas in a zone. Just make it the the main cities period (Jueno, Sandy, Windy, Bastok, Whitegate/Al Zahbi--others are far less in danger of congestion). Only reason to loiter their 24/7 is for bazaar, and that can just as easily go back to being Rolanberry and Batallia as it was for years. Was a lot easier to shop in Rolan-Mart back then...now the bazaars are kinda spread out all over.

Make it a long countdown though--sometimes people hang out there for hours trying to form up an alliance, so it does need to be a decent time frame for countdown. It should also give the player notice of the pending disconnect--kind of like the Sneak/Invis countdown with several staggered notices first, that way they have a chance to become active before getting bounced.