She should have known she was going to be censored and she should have edited her copy for review. The school officials then would have been unprepared to cut off her mike.
She DID know. The school administrators reviewed her speech well before the commencement and told her that her comments were inappropriate and had to be changed. Instead she chose to lie to the adminstrators and continue on with a speech she had already been told she couldn't give. In another thread on this topic I said she should have raised a stink about it before the commencement, but she chose not to, likely because, as sinkspur said, she wouldn't have gotten any attention for doing that.