That's the one thing keeping me from operating my own Mastodon instance. All it takes for me to be in serious trouble is some troll tooting CSAM while mentioning my account... that causes my Mastodon instance to automatically download it, and so the troll can then report me to the authorities for hosting CSAM. Or Nazi content (which is banned in Germany for good reasons). Or piracy. The list of how one can shoot themselves in the groin by simply running a Mastodon server is pretty much endless, and it's not made easier by the fact that German prosecutors are so tone-deaf regarding anything Internet that it took years to get them to stop raid TOR exit-node operators.
How people are running Mastodon servers out of Germany, or how there are people running Mastodon-as-a-service shops is frankly mind-blowing IMHO.
Your Mastodon instance is caching stuff locally. If you post something to your instance it lives there until another instance requests it. Then it lives on both instances. If your instance deleted the toot/content and I try to access it after the deletion I won't be able to get ahold of it. Same concept as IM2000.
Note I'm not sour on the idea of IM2000. I genuinely think its ideas were used by ActivityPub.
