By all means post a pic of you getting your vote in – and tell all your friends your choice – but when it comes to a democratic voting system, a little secrecy goes a long way.

New Zealand singer/songwriter Lorde has been told by the Electoral Commission (or someone else, because the Electoral Commission probably isn’t this stupid) that she was breaking the law when she posted on image of her local council voting papers with a prominent tick next to the name of one of the candidates running for mayor of Auckland.

I can clear this up: there is no law against posting a picture of your voting paper on Instagram, or Twitter, or anywhere else.

But please don’t.

Tell people how you voted. Tell them why you love one candidate, or your concerns with another. Take a picture of you dropping your envelope into the post box to show that voting is a community undertaking we all do together (actually, don’t do this now, the post might be too late, so drop them off at a library or supermarket or wherever your council is accepting voting papers in person), and in your Instagram post of you doing, tell them how you voted, if you want to.

But please don’t offer proof.

Not because it’s illegal – it currently isn’t – but because actually the secret ballot is good, and having a society where the secret ballot is valued is good too. (I know this makes less sense with postal voting, but the principle is the same.)

Proof of how people vote undermines the secrecy of voting in a way that telling people how you voted does not. A society in which people regularly show – not just tell – others how they voted, is one that is just a little more open to pressuring and bribery of voters.

There are people in long-term relationships with partners who might tell them how to vote, but who will never actually know if their advice was taken, because we have the secret ballot. A secret ballot reinforced with rules about voting in private and bans on photography in voting places. (I know this also makes less sense with postal voting.)

Why then does whoever contacted Lorde think she broke the law? It seems to be the prohibition we have on publishing imitation voting papers with instructions on them. It’s a badly written prohibition that applies to both general and local elections, but it is has never been used to cover situations that don’t in fact involve imitation voting papers: no-one is going to accidentally think they’ve voted by putting a tick on the image they downloaded to their phone from Lorde’s Instagram.

The ban is in a section of law dealing with interfering with voters, for example, by providing false instructions on how to cast a vote, or making it look like voting authorities want you to vote a particular way. If parliament wanted to extend this piece of law to ban images of actual votes, it could, but would need to be clearer.

But please, don’t post them on Instagram anyway.

(Also, voting in local elections closes at 12:00 midday on Saturday.)