The whole ContentID system is irreversibly broken as long as people are allowed to submit content for registration over the internet and not in person under penalty of perjury.

A ton of fake artists take widely used commercial sample packs and copyright-free music, create simple songs and then register them via companies that submit them to ContentID databases. They then use it to monetize content created by other people on Youtube. There is no way to report these because the listener is not the copyright owner.

Just two of the countless cases I've come across:

JasoN SHaRk - Let the Music Play. I've heard a track from an indie artist predating the release by more than half a year. https://www.youtube.com/watch?v=tEGgea4Z2co

Anitoly Akilina - A Nightmare (on My Street). This is a bold one; it uses a free track from Kevin MacLeod, also used in Kerbal Space Program. This means KSP gameplay videos get monetized. https://www.youtube.com/watch?v=wVbZT1iFnlM