No, anyone can technically vouch dead posts with 31 karma or higher. Vouching is the inverse of a flag.

https://github.com/minimaxir/hacker-news-undocumented/blob/m...

I suspect it’s more some threshold of vouching required, because I know for a fact some of the other dead submissions got vouched.

Still, this apparently completely undocumented standard behaviour seems a little bit troubling? It’s not like 404media is a spam content mill (and I doubt it is the ability to bypass the paywall - those methods don’t work on 404?)

No. Although I may not have the exact reason the domain was banned, I've been around long enough to observe that everytime a 404media.co article is posted and gets traction, the comments unanimously complain about the paywall and it gets flagkilled.

Vouching is intended as a corrective check on things that shouldn't be automatically killed.