Yes. This statement is correct.
The rules and regulations under which Notarys operate may differ from state to state. If a Notary fails to require verification of the identity of a signatory to a mortgage they would be subject to the actions called for by the statutes of their state.
A doctor can be a notary, but has to apply and pass the test like anyone else. Doctors are not automatically notaries.
I'm not certain what the all purpose acknowlegement your speaking of is - however -A notary is basically only confirms the person signing the document has been identified as the person signing it (preventing forgery). The document can say anything...even "I swear the name signed below is not my name"... but the notary assures that signature is valid. Notarys do not confirm any legal power to the document or should even be concerned with it's contents.It is true that in some States a notary can also give a legal Oath.