sources close to the situation say that Led Zeppelin owns the rights to the concert, and that the band's management requested the removal of any clips of the event.
In these cases I often wonder if the band thesmelves really care, or if it's just the legal eagles looking to protect 'Teh Int3ll3ctual Propertyz'. It's not like Zeppelin is short on money. And it's not like these clips will cut into the DVD sales ... the thing is going to sell millions of copies for ****'s sakes and if anything such clips only increase anticipation (I know it did for me).
On the other hand, maybe they don't want the ****** recording quality of most of these clips to taint the quality of the performances themselves. In other words they don't want the material out there in a ****** format, and that's fair enough I would say. Releasing a few high-quality previews on the official Zeppelin site or WMG's site would go a long way in undercutting crummy pirated footage.

On a somewhat cheerier note, I wonder if a portion of the DVD sales will go to whatever charity the concert was supposed to benefit.