Try it this way around then (to play the devils advocate)
Mom: Keep your room clean for a week and we will go to the lake on Saturday.
Child: Okay!
(Child keeps toys in toybox, books on shelf, etc, but fails to make the bed a couple of times during the week)
Mom: Nope, we aren't going to the lake - you didn't make your bed tues or thurs! (Or, in an extreme case - "You didn't pick up the dirty towels in the bathroom" which doesn't have a thing to do with keeping your room clean)
So, was it a punishment, or a reward?
(One could argue its a salary, I suppose)
If criteria are set to gain something, I'm not sure it counts as a reward, or carrot. A reward should be something that is received for going above and beyond mere criteria. Getting X for meeting Y criteria seems like a salary.