It's ripe for abuse. The intention is good, but there's no way to shield it from abuse and money.
Check the thread, some even suggested:
1. a scoring system for accounts (a.k.a. China's National Social Credit system) (federated or local)
2. labels (federated or local)
3. If a server doesn't block a user, the server should defederate, or the other admins will block the entire server
4. Algorithms
Etc.