No! the LBS is trying to screw you. First check the hanger alignment. Second check to see if you have any stiff or bend chain links (pedal backwards and if you see the derailleur jump, you have a stiff/bad link) Third check to see if you have a bent tooth on the cassette. This rarely happens but it happens occasionally. It may be bent just enough that the chain catches up on it and causes your auto shift. Then finally change out the cables and housing and check the BB guide to be safe.