[gchamonlive]

Take this post for instance, the link to the upvote is https://news.ycombinator.com/vote?id=48106316&how=up&auth=26...

If you change `how=up` to `how=down` it downvotes the post.

I tried it once, didn't change the vote count, but I issued the inverse operation with `how=un` and the vote count went up, so I'm guessing someone upvoted at the same time I downvoted. That or it doesn't really work like it says it does, but it does respond with a 301 followed by an OK, so I think this works.

[LocalH]

I tried this and had no change with either down or the subsequent un, using my own upvote link's token.

Perhaps someone coincidentally upvoted the post at the same time you attempted to undown the submission, rather than upvoting when you attemped to downvote it.

[gchamonlive]

Good to know! So the hypothesis is false.

[1970-01-01]

This.