A notary commission is a public trust exercised largely without supervision, and the background check is how the state satisfies itself that the holder is fit for it. California requires fingerprints from all applicants, and the requirement extends to those seeking reappointment rather than applying for the first time — which is the point the question turns on. The reason is straightforward: a commission runs four years, and conduct during that period is exactly what a renewal check is for. An applicant who committed a disqualifying offence in year two would otherwise carry the commission forward indefinitely on the strength of a check done before it happened. The prints are submitted through the state's Live Scan system, and the resulting record goes to the Secretary of State, which may deny an application based on convictions involving dishonesty, moral turpitude or a felony. Self-disclosure is required too, but it does not replace the check, since the check exists precisely because self-disclosure cannot be relied on.