Hacker News Reader

and then un-flagged right after?

I vouched for it.

Where's this option?

Usually the same place the flag button is. It only appears when a post or commen is flagged/dead.

It wasn't there for me. I vaguely remember it being there before though.

I think sometimes you have to click on the date to go directly to the post/comment, in order to see it.

It seems so. What a ride!