This is such a good question. We had a string of like, 20 lobbies where there was just at least 1 geared team, was kind of wild. Today was a total different story though.... nothin' but rogues and cheaters :(
from my EXP its very random. most lobbies have 0-3 geared teams. sometimes if you wipe 2-3 lobbies they go empty and its just nakeds, teamers and cheaters :/