I don't even see the big problem, hardly see any of the high levels hunting them but a few character which clearly is just there levlers on there gaining gold / items to sell gold on top of there leveling £. All the top players i know who don't have a leveler are not farming Jacko's, only see them pop up for the boss shout. i mean at peak times it's hard to find enough Jacko's to make it worth your while. Maybe early AM's it would viable.
