I was going through some flagged posts and noticed that the [delete answer] button behaves differently based on whether the post has already been deleted or not. I probably found out this time because there are more people flagging posts than normal :)
The behaviour is illustrated below:
While keeping the post closed (I had already seen it before), I pressed [delete answer] once and noticed that it didn't show a blue bar to tell me the vote had been processed. When clicked again, the confirmation dialogue asks to undelete the post. Normally I don't bother to read the contents of that popup, so I would end up casting an undelete vote.
- have the [delete answer] always cast a delete vote
- show a red confirmation popup that says "Post has already been deleted"