User student has, quite impressively, recognized that all of user6560's questions are homework questions from the ongoing course Math 620 at the University of Buffalo. I just went through, downvoted all the questions and left an explanatory comment on all of them.
It is theoretically possible that user6560 is not enrolled in the course, but simply is independently studying from the course website. In that case, I would say that user6560 hasn't done anything wrong, although they1 would have done better to explain the situation. However, in the more likely event that user6560 is enrolled, they are violating our policies on how to ask homework questions. Moreover, if they are not disclosing to their professor that they are seeking help here, then they are most likely in violation of the University of Buffalo's plagiarism policies.
My question is, should we take further action? Is it appropriate to retag the questions? Close them? E-mail professor Badzioch? UPDATE: User student has e-mailed Badzioch. Pointing this out here so that we don't flood his inbox.
On Mathoverflow, I would immediately close these down, and quite likely e-mail the professor, but I am not sure what the community norms are here. None of the meta discussion on homework seems to have a consensus on how far we will go on this issue.
Finally, let me give a word of warning from my Mathoverflow experience. We had a lot of unpleasant flame wars early on because user X would ask a question, user Y would answer it, and user Z would vote down Y's answer because Z thought that X's question looked like homework. Let's focus on X's misbehavior here, not on whether Y was acting as a sufficiently vigilant cop.
1 Yes, I sometimes use "they" for a singular person of indeterminant gender. If it is good enough for the King James Bible, it's good enough for me.