I’m sorry to say that I’ve never heard of such an instance before, but I did a quick search around and [found someone](http://talk.collegeconfidential.com/university-california-san-diego/1627796-will-ucsd-rescind-my-offer-because-of-one-d.html) who was in a similar situation last year. The last post on the thread might help you, or you can contact the OP and ask how it went for him/her.