I've known of a guy getting Fenab'd for just doing a low transition to an unrestricted climb at a controlled airport when it was requested by the controller, so the FAA isn't the only one you have to worry about. Not that a Canadian hornet pilot would care about that. But, the FAR part 91 does specifically address when you can and cannot do aerobatic flight. I don't think he ever got aerobatic, so looks like he could do whatever he wanted there as long as it was approved. The only rule it looks like he was possibly breaking was the airspeed restriction for Class C/D airspace.