- for example, 2 years ago my heroes videos started being flagged... I tracked it down to a hip-hop artist, who just took 20 seconds of music from heroes 3 soundtrack and shamelessly copy-pasted it into his song... and then of course claimed copyright of the song (including the 20s bit of course)... I filed a dispute... provided links to the original songs (by Paul Romero) and what did the publisher say against overwhelming evidence? No... just "no"... this is our music, f*ck off. I had to cut some parts out from the Heroes 3 soundtrack, so that I don't get flagged constantly.
This is a common practice, yes - I stumbled upon some other type who was flagging IK+ soundtrack by Ron Hubbard as their own. Hard to put all the blame on a petty as*hole, guys like him are just following the example of the biggest fishes, and exploiting the unfair system.
It's obvious Google has no resources to check the claims manually, no matter how big and rich they are (and not
that big actually... their stock value is in $500 billion range, but all their assets are worth maybe 5% of that, if not less), they cannot possibly have enough employees to do that, even if they employed Indians en-masse (I won't say Indians are bad workers in general, but there's a saying in Poland, "like pay, like job" - cheap labour works poorly). That's why they have this automated system. Just another example of how foolish the current form of copyright laws is in the age of internet (I won't say "outdated" laws because 1980s intellectual copyright rights were less harsh than todays').
Another thought, maybe that's why your Christmas song got garbled - the automated system processes all uploads nowadays, so maybe it decided the song is copyrighted and garbled it on purpose - because if it's garbled, it's not a violation. Or maybe it was just a bug, there's no such thing as software without bugs.
EDIT:
Tinfoil hat mode: activated. The real fun will start if/when the current IT stock bubble bursts and Google gets bought by, say, Sony Entertainment, or gets partially nationalized by the US govt (like General Motors was). If you have any rare gems faved on YT, better DL them and burn them onto DVD-Rs while you still can