Yeah, i know what you mean. Despite RG's whining about this, it's not just homework questions. We had some joker from England who asked about driving from New York to Toronto, and he got detailed answers about routes to take, gasoline prices, where to stay, how much it would cost, sight-seeing in Toronto--that sort of thing. He got good, detailed answers, and then came back a couple of weeks later to say he had had a good time and thanks to all concerned. My personal reaction was, well, alright, that was worth the effort.
Except that it wasn't--that was the first, but not the last time i answered such a question. It was the first and
the last time anyone came back to say thank you. I avoid those kinds of questions now, unless it's someone we already know here who is asking about a city or a region with which i am familiar.
It ain't just the homework kids who can by snotty about these things. Once again, taking the example of the Chinese ESL students, it wouldn't be hard for them to say thanks, and it would make a world of difference. Even if i sometimes get irritated with the ESL students, i give them the big benefit of the doubt, because they are scrupulously courteous.