It is true that AH have been camping far back more frequently lately. But again, how would you enforce any rule against that?
First, they are very mobile in comparison to the AA, so they most likely wont be camping by the time an admin sees any !report. This is already the case, most of the time, for the AA
Second, how can you tell between someone camping or just retreating to reload? I don't think you can.
So, though it would be nice to eliminate people camping behind the hill in the AH, I don't think there is any practical way you can do that.