Hygiene

[superfun]

Suzie Homemaker, those examples aren't really good ones. Yes, some restaurants charge more if there's food left over on the plate. It's not because they have to scrape the dishes, but because you ordered too much at an "all you can eat" place, and you wasted their food. So by your example, if a restaurant can charge more for wasting, then I should charge more when kids waste my food?
We aren't in the same business as a restaurant, or a window washing company (which I would assume would charge more based on how dirty the window is), so we can't compare our business's to those ones.