A certain user posted a question today, received an answer (from myself), accepted the answer, then deleted the question sometime afterwards. I now find that a very, very similar question has popped up from the same author. It seems as though they are working through a series of homework excercises, are having Math.SE answer their questions, and then deleting the questions to avoid suspicion. Not to mention, users who write answers to these questions are wasting their time because of the deletion. It's not generating Q&A content for the site when it's deleted right after the OP gets their answer...
I don't have the capability to check whether the user has engaged in this behaviour in the past or not, so admittedly I am speculating.
Nonetheless, what's the protocol to deal with this situation? I can find other questions on Meta about users posting homework questions, but nothing about what to do when they are engaging in this deletion behaviour.