I am a fairly young teacher, and I teach in the same high school I graduated from. Therefore, I know a lot of the parents of the students I teach and coach. I had a relationship with the parents prior to teaching their kids. Therefore, there have times where that parent comes up to me and asks me about a student other than their own because their child is about to start dating them or hanging out with them. Unfortunately, I have to tell these parents that I cannot discuss with them another student that is not their own. How can I express this to the parents without straining the relationship that I have had with them for many years prior?
Even though you feel uneasy about the measures you have taken to stop this behavior so far, it seems to me that you have done the right thing. This solution, sharing that you do not wish to harm the current status of your friendship, but also that you cannot disclose that kind of information, is really the best. Is those asking are really your friends (no matter how casual the friendship is) they will understand and appreciate your professionalism.
I agree. If they don't understand and keep trying to overstep your boundaries, the relationship is probably not a great one anyways.
If you have a relationship with the parents prior to teaching, then chances are that you may know the student, therefore, this can send a message that you are not being honest about not knowing much about a particular student when in reality you do.