I'd imagine there are many threads about this.
Why can't you just have it so that when a player DC's from the game for whatever reason, the following log in attempt states "you are already logged into the game" and forces that connection to be dropped...allowing a subsequent login to actually work?

DC'ing right at the end of a dungeon and not being able to log back in for 10-15+ minutes will almost always mean the party kicked you for being Offline.
A bit unfair when you wasted all that time trying to get your Roulette done and go to bed for the night.