They do! In some way.

For eager ones link to userscipt.

Hi everybody!
You know, our universe is pretty unfair place. Luckily, some unfairness can be fixed. And I found a method to make this world a bit kinder!

Let me introduce a plugin that can help people overcome difficulties in their lives and develop their self-esteem!
I believe, every active member of codeforces community at least once faced the problem I've faced couple times. It's when you try to reach that sweet green arrow to support commentator but instead of this you accidentally punch the red one with all of your might! And there is no way to correct the mistake!

So, I spent some time studying the problem (and jquery, btw) and made a cute little script that changes concept of vote confirmation. While you are on a page, you now can alterate between your decisions as much as you wish (though only on comments you haven't voted for before entering page). Changes will be applied on site closing (it can be either moving to other site or closing tab/browser).

I'm not sure about the reasons but the fact is that sometimes not every vote is being applied. To prevent loss of your grades I also added special button to save everything. It can be found on panel with new comments counter (or in that place if there are no new comments).

I will dublicate link to script, if you miss it in the beginning. It's a simple userscript that can be run in chrome-based browsers (via tampermonkey plugin), firefox (greasemonkey) and opera of older versions (violentmonkey).

If you found any bugs or have some suggestions feel free to notify me via pm or in comments.

Happy New Year!