Suggested at https://meta.wikimedia.org/wiki/Special:Permalink/17346332#Vandalism_at_CopyPatrol. See also T178681 and T178682.
There was a sockpuppet who was blocked and then went on a rampage on CopyPatrol. T178681 will prevent blocked users from doing reviews, but just as we see on-wiki, the sock could create another account and go right back to CopyPatrol (before they are blocked on the wiki).
The enwiki users are suggesting only allowing extended-confirmed users to use CopyPatrol. This sort of makes sense, because we wouldn't want new users doing copyright patrolling on the wiki either. Extended confirmed (30 days tenure, 500 edits) is a reasonable threshold to ensure the user roughly knows what they're doing. However projects other than enwiki might have different opinions. Perhaps we could make this configurable on-wiki, like we do the whitelist.
If anything, it's probably safe to require the user be (auto)confirmed on the corresponding wiki.