Preventing abuse of the trust system would be crucial for Discourse in general, right?
I’ve had some success with preventing same-IP like/flag actions, and I’d see that applying with pass/fail approvals, as well… if you share an IP with a 0-level user, you can’t approve their posts.
Obviously a single IP can represent a lot of different people, but I thought it was a reasonable enough tradeoff to miss a few legitimate inter-office or inter-school thumbs-up if it made it more obnoxious to game the thumbs (or approval) system.