ContentID stores some kind of hash to identify music; isn't this "hash" just another version of the same work and therefore subject to copyright?

My point is it's likely that ContentID needs some kind of permission from the artist to even work, because in order to identify someone's music it needs to store that music (or some representation thereof), and if it does that without the artist's permission, it's infringement.

So one option could be to get out of ContentID entirely and then forbid Google to go after her fans.