ThatOwlWoman
Not Nice
That is already addressed by provisional ballots. People who vote early by mail have their ballots opened and checked when they come in. If there is a problem, they are notified and they must show up on election day to vote.
Here we must sign the outside of the envelope that our ballot is in. If the signature doesn't match that on file, you are notified and given a chance to come to the voting office to perfect it. If you don't, it is discarded. They cannot open/count ballots until election day. The envelopes with the ballots are entered into the state's election database, which you can access to make sure that yours was received and logged.