Whenever someone complains about why their shared video link on YouTube ‘won’t work’.
It works, but people largely forgot that Google stupidly ruined that ability for everyone by making it mandatory that you be logged in to watch videos, so you’re not flagged as a bot. But, since you’re sharing a link to the video or embedding it, you can’t watch it anyways because the stupid prompt shows up, forcing you to go to the site itself.
I think there’s a perfect middleground between banning reposting existing topics and no moderation. You don’t want to create a StackOverflow situation where people can’t ask a question because someone asked a similar one 15 years ago