One of the best things about the Fediverse is that it’s easy to hide posts with certain hash tags. This is far more valuable than content warnings. People put a content warning on things they know other people might want to see, but they put hashtags on things for discovery. Don’t put hashtags and the only people who will see a post are your followers and anyone who follows someone who boosts it. Do put a hashtag and anyone following that hashtag will see it. This means that there are incentives to put hashtags on posts. And so the filtering is keyed to metadata that people are incentivised to provide.