Earlier quoted context omitted.
Considering that most DDOS attacks come from zombie bots installed on programs when people Torrent, I'm suprised that there were arrest made based on IPs
I know. I was thinking the same thing. How does an IP address translate to a human being?
It really raises question as to whether you can trust something as flimsy as an IP header given the technical sophistication of Anonymous. These people could well be innocent and in fact victims of anonymous directing attention away from itself and towards these innocent victims. When Anonymous can gain control of HB Gary and FBI/CIA assets imagine what they could do to an off the shelf system that hasn't been through the rigorous security protocols that HB Gary, the FBI and CIA follow.
Given the mutability of data on a USB stick I'd also be very interested to see the chain of custody on that data and how it might have been modified. Also, the defense should request access to the source code for the IDS system in question so that it can be examined for bugs and problems that may affect its ability to generate reliable evidence.