Easier to ask for forgiveness than permission. I'd want to go in circles until I felt the warning signs of a slide.
He should've been pulled off track by a CR the first time and reminded of the rules, the second time she should've been pulled off track for the session, and reminded of the passing rules. If it happened a third time he should've been pulled for the day imo. Its not hard to follow the rules. Those rules are in place to prevent EXACTLY what you felt/ experienced. You should have kept riding while he got booted imo. If he was fast enough to get bumped to I from novice, then going around the outside or out-driving someone out of a corner to make a pass should be no problem, you shouldn't have to stuff someone into a corner. You obviously knew who it was, why didn't you approach a CR or the event organizer and told them about the situation?
FWIW, if you haven't actually tipped into the corner, its usually fair game. But if you had already set a line and tipped in and he came up underneath you, thats definitely a no-no.