Come to think of it, you're right. When Steerpike was using them he kind of locked them away & told them how good he was making things for them when he brought them food. Then when they finally caught on, they set up a booby trap (an axe on a spring, I think) to behead him the next time he came, only it didn't work & he got mad & just left them there...
Eww... come to think of it, I think he went back yrs. later & sang at/ danced with the leftovers... Ick, I had forgotten the really gross parts since then I suppose...