From NIP-56

"Relay behavior
It is not recommended that relays perform automatic moderation using reports, as they can be easily gamed. Admins could use reports from trusted moderators to takedown illegal or explicit content if the relay does not allow such things." - end quote.

Highlights the problem: easily gamed.

The solution is to only use NIP-56 events from peers that each individual chooses on their own behalf. Maybe the follow list could be used, or optionally a separate list for this purpose only