It is done precinct by precinct, and I think in batches of 100.
So, if you have a batch of 100 votes, you are supposed to have 100 envelopes or peoples names that voted in-person tied to those votes, even though you don't know which vote goes to which envelope / person.
If you lose 10 votes out of that batch of 100 for no signature on the envelope, you first try to identify any absentee ballots, which are marked as such as they are filed away. You take those out at random first. If you still have too many ballots compared to envelopes, you take out more at random.
So, the impact should be contained to the precinct that the fraud occurred.
If someone just dropped in 500,000 mail in ballots, you are going to have a lot of ballots with no envelopes.
Here is a link to the latest recount manual in WI: https://elections.wi.gov/manuals/recount
So, if you have a batch of 100 votes, you are supposed to have 100 envelopes or peoples names that voted in-person tied to those votes, even though you don't know which vote goes to which envelope / person.
If you lose 10 votes out of that batch of 100 for no signature on the envelope, you first try to identify any absentee ballots, which are marked as such as they are filed away. You take those out at random first. If you still have too many ballots compared to envelopes, you take out more at random.
So, the impact should be contained to the precinct that the fraud occurred.
If someone just dropped in 500,000 mail in ballots, you are going to have a lot of ballots with no envelopes.
Here is a link to the latest recount manual in WI: https://elections.wi.gov/manuals/recount