How it played out, very short version: I got up in the morning and checked the new signups, part of my morning routine. We have to check for spammers and shills on a daily basis to keep mefi free from linkfarming and bullshit self-links and so on, and that tool is step one. The paypal info that comes with the $5 signup fee is hugely helpful for profiling likely spammers.
I noticed what looked like a signup from Adams himself; person I've heard of signing up happens now and then, it's an "oh neat" moment and that's about it, since if you're sticking to the community guidelines and participating in good faith, who you are and what you do and how anonymous you choose to be is entirely your business.
Unfortunately, what I saw when I checked out his comments since signup was weird aggressive pretending-to-be-a-third-party arguing about himself, which is really not an okay thing to pull on mefi. I talked to the rest of the staff, we sent Scott an email saying "you need to either let folks know who you are or stop having this proxy argument about yourself as if you're someone else".
Time passes, no response from Scott. Then he posts that "who thinks I'm Scott Adams?" comment. Gave him some more time, still no reply, left the "check your email" comment. Time passes, and then, still no response to us, he drops the disclosure in the thread.
If he'd chosen to walk away, that'd have been fine too, and we'd have had nothing to say publicly about what he did regardless of how obnoxious and sketchy it was. We took considerable pains NOT to out him and make it his call how to proceed.