Australia has a system where you are anonymous and can prove that you only voted once:
You have to be registered and must vote within your electorate, so your name appears on a certified list for that electorate and each voting location has that list. When you vote, they strike your name from the list.
After the election, the lists from these locations are compared. Anyone who votes twice has their name struck twice, and are investigated for electoral fraud.
Whether people know if you voted or not is immaterial, as voting is mandatory in Australia.
How does that prove that you only voted once? If I know someone's name and address (and by extension their electorate) I can rock up and vote as as many as I want.
Then you go to jail (penalty is 6 months for impersonating a person and voting on their behalf.) It's not like polling locations don't have cameras.
(A few people voting more than once is unlikely to change the results of an election. If enough fraud is detected to impact the results, they'll run a new election.)
> It's not like polling locations don't have cameras.
Given they are usually random primary schools and churches... do they have cameras?
I think the bigger deterrent is just the risk of claiming to be someone who already got ticked off at the same booth, which would immediately raise suspicions.
You have to be registered and must vote within your electorate, so your name appears on a certified list for that electorate and each voting location has that list. When you vote, they strike your name from the list.
After the election, the lists from these locations are compared. Anyone who votes twice has their name struck twice, and are investigated for electoral fraud.
Whether people know if you voted or not is immaterial, as voting is mandatory in Australia.
Works pretty well for a paper system.