Occam's razor
I think Occam would disagree. You're hypothesizing that there is corruption in DT and you're making a fairly complicated set of assumptions that signature campaigns have something to do with it (without providing any specific path of how that would happen, let alone examples). Occam's razor would be picking the simplest possible assumption, which I think would be that if someone wants to corrupt/bribe/etc a DT member they can do so regardless of them being in a signature campaign.