16. Can’t someone else just take my ballot, mark it, and send it back without me knowing?
That is possible, but … it would be seriously illegal.
Also, you could find out that a ballot was submitted for you by checking online. And, it is unlikely that the signature would pass muster. Del. Hansen’s bill lists detailed characteristics for signature verifications (based on Oregon’s published best practices). You would be notified if the ballot returned “for you” and the signature did not match.
Del. Hansen’s vote by mail bill has made every attempt for vote by mail to have better security than our current system.