Led Zeppelin YouTube Culprit: Overeager "Bootbusters"

We've spent the last day or so trying to figure out why YouTube has been taking down clips of Led Zeppelin's reunion concert: Google's video service initially said it was doing it at Warner Music Group's request, but WMG employees have told us it wasn't them.

Now we have a fall guy: GrayZone, a Brooklyn-based outfit that "provides investigative, paralegal and research services to members of the entertainment community." In other words,  a shop that's supposed to help companies like WMG ferret out illegal recordings on the Internet; apparently one of their services includes sending takedown notices to YouTube.

Here's the statement that showed up in our inbox last night, attributed to a Dorothy Sherman at GrayZone:

Grayzone regrets that it erroneously issued takedown notices to YouTube regarding footage of Led Zeppelin’s December 10th concert.  The error is ours alone.  We acted without authorization from the band or Warner Music Group.  Unfortunately, an automated system mistakenly attributed the removal of the content to a copyright claim by Warner Music Group.  That was inaccurate.  We have informed YouTube of the error and we regret any inconvenience this may have caused.

We have a bunch of questions about how this actually happens, and if we get any answers, we'll pass them along*: In the meantime, plenty of cruddy recordings of the show are easy enough to find. Example after jump.
Update: We had nice chat with Dorothy - details here.