Frank's idea sounds like a good guideline - provided, of course, that "homework questions" are actually a recognizable species. Some definitely are.
Ultimately, I feel it's all in the tone and attitude of the person asking the question. It all comes down to the ratio of the amount of work someone is willing to put in, and the amount of work they expect others to contribute. Stuck on a homework problem and using it as an entry point to get to know the Wolfram language and actually learn about a new learning method? Great, even if it means a lot of explanation work for us. Copying the assignment here, hoping that one of the stupid nerds will do your work for you? Not cool, even if the answer required from us is a one-liner. And honstely, I do believe that most of the people here will sense the difference between those two just fine, and will accordingly answer - or not. Do we really need a fixed rule and moderator intervention for that?
Also, I really don't see it as my responsibility to tell any student how to do or not do their homework. If someone doesn't want to learn but just wants a quick answer, that's their own business. And if anyone here wants to answer their questions anyway, why would the rest of us take issue with that? Who does it even hurt, aside from the original poster of the question?
