The DMCA law itself says the host can't require any such verification, and if YT started requiring it for ContentID, the complainers could just start sending regular DMCA takedowns.
which is better, because regular DMCA claims comes with a legal repercussion risk - you cannot file a false DMCA claim without punishment from the law.
But youtube contentID claim is not DMCA, and has no punishment attached for a wrong claim.
