I'll note that France has a slight variant on that, where it's assumed that any identifiable marker of the ballot could reveal a voter's identity, bad in case of blackmail like "vote for X, and show it by having a stripe at at the top, or I [do bad things to family], I'll be checking the ballots").
To avoid this, no markers, but all possible votes are pieces of paper with printed text, grab N>2, go in the booth, put in one in an envelope.
This way your vote and any other vote look identical, and vote is voided in case of any identifying mark (even weirdly bent paper etc).
No stamp needed, just number of votes/envelopes.
To avoid this, no markers, but all possible votes are pieces of paper with printed text, grab N>2, go in the booth, put in one in an envelope.
This way your vote and any other vote look identical, and vote is voided in case of any identifying mark (even weirdly bent paper etc). No stamp needed, just number of votes/envelopes.