I work the elections in a small Michigan town. At 8 p.m. we close the precinct and anyone that had an application to vote, gets to vote. Then we begin to close the machines down. One of the first things we do is to send the report from the Poll Book to the County. Then we raise the antenna on the vote tabulator and send those results to the County.
It's always seemed to me that a determined hacker could find a weak link in the sending of info.
After the machines are all turned off and info has been sent, the ballots are taken - in locked metal bins - to the Twp. Clerk. A Dem and Repub have to deliver them together.