Wisconsin

Witnesses have to sign, date, and list their address. Those are checked by the clerk before election day and/or the poll workers before opening envelopes containing ballots on election day. For 8000 ballots, you'd need 4000 different witnesses with valid addresses and distinct signatures just to avoid raising alarms.

Also, in non-COVID years, clerks send election deputies to nursing homes to conduct balloting in person. Observers are allowed to follow the deputy around. I did this in 2008 in several precincts with large nursing homes in my county. Each county would have done this differently in 2020 because of COVID and each nursing home's safety restrictions. The "indefinitely confined" who would NOT fall under this service are those who are not able to get out of their own home or at assisted living centers on election day. That's an even harder number to come up with.

You still need 8000 names with birthdays and addresses just to request a ballot as an "indefinitely confined" through MyVote and, as the article points out, you'd have to know they didn't already request one or, worse, show up at the polls to vote.