What good does it really do? If I put a line on the translation in both languages, saying that I translated the agreement dated xx-xx-xxxx to the best of my knowledge and sign/date this statement, then all the notary could certify would be that he saw both documents on a particular day, and saw me. So if the new client trusts me and signs it, what additional value would the notarization provide?
I mean, it's not expensive of course but I'd have to drive there.