I had tagged this question with the tag [not-homework] after one of the persons answering it had wrongly assumed that it was homework.
This tag was removed by moderator @KennyTM. I would like to understand why.
I think a [not-homework] tag will save a lot of the inconvenience caused from having to ask and answer the "is this homework" question or from people assuming on their own that a question is homework.
You can take the position that a certain type of question should get the "homework" treatment regardless of whether or not it was assigned by an instructor. In that case we should also do away with the [homework] tag.