I will always downvote answers or questions that deal with violating Facebooks TOS.
You have the right to vote as you please; your policy is perfectly valid. I personally, however, would look at which part of the TOS is being violated. If it's about circumventing some ridiculous, borderline illegal provision that common sense dictates should be scrapped immediately, I can see myself even upvoting.
Since facebook started directing all technical QA about using their platform to the facebook.stackoverflow.com filter, should these posts be flagged and ultimately deleted.
I don't think anything should be deleted because it violates a contract that SO is not party to; we are not here to enforce Facebook's (or any other company's) interests. Stuff should be deleted because it's bad content. SO's own rules are perfectly sufficient for making this decision.
In most cases, questions or answers discussing TOS violations will probably also be delete-worthy under SO's rules. But there's no reason to cast this into stone.