"Illegal", when describing notary behavior, would indicate the notary is wearing the notary hat, not the signing agent hat, and does something forbidden by law. Sitting and watching the signer alter the documents is not illegal.
The title company may not like it, and the NSA may not be doing a very good job as a signing agent, but it isn't illegal.
If the signing agent isn't a lawyer and is the one who suggests it, it might be unlawful practice of law; that would depend on the circumstances. |