A lien that has not been perfected but the predicate of which has occurred prior to the closing is known as an inchoate lien. I think that title insurance polices universally exclude inchoate liens from their coverage. that is why the seller is usually required to sign an affidavit at the closing that there are no facts which would give anyone the right to file a lien.
Oooops! This is an old topic. Well, its a good answer from me to the OP's question. Sorry I missed it when it came up.