Relays admins will examine the reported users, and only the real spammer will be banned.
Discussion
I guess that's good. Although the most notorious spammers keep making new accounts.
That will be stil a issue, indeed. Is the same problem for email, where the problem has been limited with spam algorithm and whitelist/blacklist
The easist solution will be using only relays who ask for a entry fee on relays for posting. Honest user will pay only some sats while spammer will dry run after a while (supporting the relays)