Is "some jurisdictions" such as Italy the entire world? Is the seller based in one of these countries? Is the forum hosted in one of those countries? Are customers from those countries even trading with him? No? You don't know? In that case NOTHING HE IS DOING IS AGAINST THE FORUM RULES.
I have no idea about the legal situation, however I would like to remind OP that Microsoft is the largest company to accept Bitcoin for some of their products and you are not doing them a favour by selling MSDN. I care a lot less about him violating the ToS of companies that are unwilling to integrate Bitcoin.