This has probably been posted before however I think if its not too hard to implement the best method to tackle disconnection is to approach it in the same way as an MMORPG, since there are similarities between the two, in other words a timer of about ten seconds when the abort button is clicked. That way the player cant simply DC right in the heat of combat, I'm just not too sure how this would prevent alt+f4'ing, maybe change it so that if you alt+f4 your character doesnt actually disconnect for 10 seconds if possible? Like I say I don't know how hard it is to implement something like this so forgive me if its an unreasonable suggestion.