I'm sure that makes it worse. Memorize the MOTB locations for each map and camp it?
Also, when I say camp till MOTB, I don't mean stationary camping. I'm talking more of a huge mob staying together and picking off the few that come close, but staying away from the main fights overall until MOTB and rushing.
As long as the MOTB locations are put in places that offer no specific advantage (disadvantageous spots work fine too), then there's no problem.
I think you're grasping at straws with this mobile camping idea. A mob that stays together for strength in numbers isn't anything unfair. And where are the "main fights" for this mob to avoid if they are main force for the team. Either there are no major battles because the mob consists of the majority of the team, so the entire opposing team comes at the mob, or the mob is just a significant portion of the team and is letting the rest of the team get slaughtered as they avoid the battle and leave their allies outnumbered.