My students tell me they consider it 'impolite' to merely say "I don't know", even in English.

I read this this morning, and it wasn't the first time I've read such things about China either.

But strange to say, in my experience (been here five years now), the Chinese have no problem whatsoever admitting they don't know when they don't know. I spoke to some students about it today myself. They didn't think it was a part of Chinese culture at all.

Could it be regional? Could it be wrong? Could things be changing? Could China be such an amorphous, fluxing mass that few generalisations validly apply to it at the moment?