How did someone find out?
I don’t remember the whole story. CGEB was just another FReeper, is my recollection. Not particularly outstanding, other than the clever and memorable screen name. One day he/she was zotted, and there was at least one thread about what had happened.
There were worse false-flag FReepers back then. I won’t mention any names. One was a stalker, as I recall, and got arrested in DC. Something about a big-time DC law firm. I don’t remember the details. Again, no names...
It was true. Forget how he was outed. (I had a different screen name then). I do recall that HLL (Hillary's Lovely Legs) had a running battle with CGEB and had figured out that CGEB was a guy. Don't know if she was the first to discover it, but I would not be surprised based on her profession.