As a public official, the notary public harms the public trust by failing in their duty to confirm identity. If a notary public in a given state doesn’t confirm identity and a loss occurs, an injured party can file a claim against that State for the loss, because the State was negligent through its appointed representative.
A surety bond is a guarantee of payment to the obligee (the State) should losses occur for a penalty amount of the bond. Notary Public bonds are usually provided by a surety company (typically an insurance carrier). The bond generally runs concurrently with the period of a notary’s commission.