I used to be a teacher and received training to instruct exactly as you describe. The idea is that students are supposed to ask each other first, and if no one else in the group knows, then they ask the teacher. I have very mixed feelings about the push towards group work, but I will say that in much of the inner-city, asking a peer for help on anything is considered pitiable weakness. So the idea of getting kids to learn to work together and help each other when they can, is, at least in it's conception, not altogether terrible.