I think the webcam idea is a great idea.
I also think all electronic voting should give the voter a printed receipt that shows their timestamped vote, and a paper copy of that receipt should be kept by the machine.
That way there is a paper log that can be used to challenge the machine totals. And the web camera can be used to confirm that the number of people is accurate.
Wouldn’t a time-stamped receipt for the voter and one for the machine identify the voters’ ballots, and how they voted? That obviates the ‘secrecy’ of the ballot.
At our polling place, each machine - 2 computers and 1 optical scanner - had a counter. At the end of the day, the number of votes cast on those three machines has to match the number of voters who checked in for a ballot. The number of electronic votes and paper ballots has to add up to that same number. Every paper ballot distributed to the precinct has to be accounted for.
There are a number of safeguards, but if you have corrupt people running the elections, as appears the case in certain Philadelphia precincts, maybe we need some Eastern European UN poll watchers there, and not in TX.