The use of this LOIC tool that this group are encouraging people to download onto their PCs and fire up to launch these DDoS attacks will be easily detectable and tracable. I'm sure that the companies that are being attacked will be keeping records of the malicious traffic, to be passed on to the police who will, in turn, be able to tie the IP addresses back to broadband connections.
So, I wouldn't be surprised if we see raids, confiscation of computer equipment and (in the UK, at least) charges brought under the Computer Misuse Act. I wonder what the average decline in income is, due to one's inability to get certain jobs because of a criminal record.
And, by the way, those who think that they can get away with it by claiming that it must be a virus infection are deluded - forensic examination will reveal the deliberate downloading of the LOIC tool.