Everybody doesn't use the same versions of operating systems or browsers though. It's not just a case of oh he uses windows and firefox therefore we've caught him. The admins can see the IPs and detailed info and users are vastly different and if two people are using the same proxies/tor and logging in and out from one account to the next it is blatant.
If the two alt accounts go from using:
Mozilla/5.0 (Macintosh; Intel Mac OS X 10_10_2) AppleWebKit/600.3.18 (KHTML, like Gecko) Version/8.0.3 Safari/600.3.18
&
Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/40.0.2214.91 Safari/537.36
Both to
Mozilla/5.0 (Macintosh; Intel Mac OS X 10.5; rv:16.0) Gecko/20100101 Firefox/16.0
Which is the same as WoodCollectors then that's pretty damning evidence.
I suspect - oh noez suspicionz - that WoodCollector took over one or both of the accounts at some point and the switch would be obvious to the admins especially if they went from using their own IPs/computer(s) to the same connection / computer WC does. If that's the case the evidence builds up pretty fast, but of course only BadBear knows what dirt he has but I trust his judgement and like you said he has no reason to lie.
That's exactly what I meant with the pattern recognising. Although, for some reason I just assumed most people would be up to date on their web browsers, because of the auto updating software which normally comes with the browser, unless you choose not to update. Although, with Tor browser none of this applies as it appears that every user is using the same operating system and browser version. I would put money on Badbear having enough suspicion/evidence.
Besides, Badbear has gained enough experience over time and probably can identify them before gaining as much information as that.