Should Vettel be banned?

[Starter]

I don't know where you're getting that from. It's never been the standard in any form of racing from club to international.

Actually, you are mistaken about that. It is always the responsibility of the car behind to avoid contact. I'll refer you to the Sports Car Club of America's General Competition Rules (GCR) to confirm. SCCA is the largest sanctioning body for club racing in the world, so it's not just some off the wall local group.

In the case of brake checking, that would be covered under unsportsmanlike conduct.