Big time. Biiiig part of the reason I don't run an instance anymore. Granted with any open and free network its bound to be an issue at some point.
Mastodon is a cesspool. https://www.theverge.com/2023/7/24/23806093/mastodon-csam-study-decentralized-network
Discussion
right. this could absolutely happen on nostr. and we don't have any tools, by design, to stop it. we can just mute/block and move on. relay operators could get contacted by authorities to remove content though.