> That opens the possibility to observe people picking up the paper of $CONTROVERSIAL_CANDIDATE and dropping it into the box, thus revealing who they voted for.

> That opens the possibility to observe people picking up the paper of $CONTROVERSIAL_CANDIDATE and dropping it into the box, thus revealing who they voted for. You are supposed to pick at least two papers and usually there are enough paper so that everyone can pick one of each. Then you go to a booth, hidden behind a curtain and put one of the paper in an envelope (given after the official has checked your elector's card), discard the other paper in a basket case, then drop the envelope in the ballot box. Of course it limits the possibilities of the vote: one person can only vote for one candidate, on the other hand, it's easier to understand for the voters.