ABQ, mine had that idea about "dishes" too! (That it was just plates, and glasses and bowls were not included.)
We do direct, on-the-spot, one-sentence instruction when we catch one of these misunderstandings: "When I say "dishes," I mean all the eating utensils, including your glass and cutlery."
Mine also had trouble with implied instructions: he regards "Class, we are on page 43" as information that doesn't apply to him, but if you say "turn to page 43" he is more likely to do it.
I suspect each instance of this kind of semi-figurative language has to be taught: it's a language glitch and a thinking glitch. Having teachers watch out for it and instruct as needed may at least get everyone on the same page.
DeeDee
