Penn and Teller, in one of my favorite jokes of theirs, say that an unwritten rule of the cups and balls trick is that you must not ever perform the cups and balls trick with clear plastic cups.

However, magicians do frequently make something about a trick of theirs transparent - figuratively or literally - as a way of making you more surprised when they pull the trick off anyway. You were looking in the wrong place, at the transparent part of the trick.

That's not to say transparent boxes are a bad idea. They really do make some attacks harder.

It's local volunteers counting their local votes and the public is welcome to witness it (if they manage to behave and not try to disrupt the count).

Until the proceedings are done the ballots do not move more than a few meters from where they were distributed and filled out.

Switzerland regularly manages large referendums on paper just fine and AFAIK they use a similar system.

But then these countries all vote on Sundays and with a sufficient number of polling stations (and higher voter turnout) so it usually takes no more than a few minutes.

The US has some serious operational problems regarding it's election system even before talking about the political side.

The same way the cops do it. Each bag of ballots has a chain-of-evidence protocol like the cops do.

Ballot boxes are opened by two people, one from each party. The ballots are put into the ballot bag, which is sealed. Both people then sign the bag and log its serial number. Every transfer up to the voting machine is witnessed and logged and signed for by two people, one from each party.