[pjc50]

People (ab)use the flagging system for that. I've seen plenty of categories of article that get upvoted onto the front page and then instantly vaporized off it by flagging.

[abustamam]

I use a pushbullet channel for HN500. I get a notification whenever an HN submission hits 500 up votes.

It's not common, but every so often one of these submissions will be flagged by the time I get around to clicking the notification.