Maybe run a DPS check, and if you're severely under the average DPS/Heal per second (maybe offset for tanks) then it becomes possible to boot you. This should be very generous so it's really meant for people trying to AFK for a CM run etc

I'd say you'd have to be really below average to qualify for a boot, maybe if you're using a lvl 30 weapon in a 50 dungeon and don't know your rotations - or obviously AFK.