Helping with homework, or letting your child fail?

In my very first year of teaching music to teenagers, I set an assignment for my Year 7s which required them to make a very simple musical instrument, based on what they'd learnt in class.

On the due date all sorts of wonderful and complex creations appeared on my desk, the vast majority obviously made by parents. Children are generally very honest and at that age have little clue about the true purpose of homework, only really understanding that they'll be in trouble if they don't do it. Most confessed straight up that it wasn't their own work.

I wonder if some parents just thought the project looked like fun and let their vanity take over. (Sorry, but your child's teacher is NOT interested in how well you can do the work. Butt out.) No doubt a few were actively trying to boost their child's grades or give me a false impression of their child's ability. But I'm quite sure that most were trying to be helpful.