User blog comment:Spawny0908/UPDATE!!!!: The Free DLC pack is coming in...../@comment-107.5.143.219-20110906225611/@comment-3455248-20110908172810

Spawny, I just added a note to Title Update 1.07 about the upcoming Undead Overrun change - Rockstar posted details on exactly what they're planning (which includes the ability for players to quit and retain XP if other players are being jerks and unduly prolonging things).