As a Notary, when you do an Acknowledgment, the signer does not need to sign in your presence (in most states). However, they need to appear before you and sign your journal. You must check to see if the signatures match the ID, journal and document. If they don’t, you have a big problem. Also, make sure the person looks like they do in their ID, and note down their ID information in your journal which of course you keep because you can get in trouble if you don’t keep one even in states that don’t require it.