From my understanding he tried to go around the convention's media policy and then make an incident out of it. After being warned 4 times they had enough of his shit and took his badge and told him to get out. He later went on Twitter and tried to play victim and bitched about "pony politics hitting a new low". The vice chair of the convention saw it, called him out over Twitter and gave a brief rundown about what happened and said a press release regarding the incident will be released.
As for what he did. I heard something about him trying to get backstage to talk to a VIP without a press release badge or whatever; he was somewhere he had no reason to be at. He also apparently upset a VA to from another comment I read on Horse News:
There WERE witnesses who aren't Draft's underlings, and BABs staff (including Obsidian) handled all this the best they could, but he fucked up, pissed off a VA, acted like a little shit kid when called out for violating con rules (the fucker seriously HID in a corner to escape detection where he wasn't supposed to be), and it was time somebody actually stopped giving more candy to the child in the supermarket throwing a shitfit. -Babsconanon