I've turned on "Check signatures" on Snort which makes the client actually check if notes are signed by their authors and.... my computer doesn't like it very much!
Discussion
I assumed most clients validated signatures maybe automatically through nostr sdk libs, I guess not then.
A sampling approach per relay might be better than checking every message. Do relays check?
I would presume putting a list somewhere of notes that have already been verified that relays and clients could access to avoid repeatedly verification is overkill?