This is absolutely doable, and is really the logic behind most current physical election security procedures. Procedures are designed less to prevent tampering

This is absolutely doable, and is really the logic behind most current physical election security procedures. Procedures are designed less to prevent tampering than to make tampering obvious. Re-voting can theoretically be done, because (public, real-time) records are kept of who voted at a particular polling place, not counting provisional ballots - look outside for a "street index" at your polling place. (Source: am volunteering for the second time working the physical polls.)