But we really don't know what those suitably qualified professionals are and are not aware of in terms of AE911Truth's claims.
I'm very dubious about the validity of comparing people who signed the petition to people who, for all we know, may not have even heard of the petition or any of the claims that AE911Truth makes, or even the organization's existence. That's why I think there should be another petition that people can sign where they
actively state that they are familiar with the claims of AE911Truth and they do not agree with them. I started a thread about it a while ago:
http://www.internationalskeptics.com/forums/showthread.php?t=275097
If AE911Truth really is just an appeal to authority to convince lay-people to sign on and donate, then a much larger number of professionals signing on to an opposing petition would be far more effective in convincing lay-people of AE911Truth's disingenuousness than appeals to 'every other professional in the field'.
We can't just assume that everyone who hasn't signed the petition, relevantly qualified or not, knows about the organization and disagrees with its claims.