I have seen this before. I think it is a powerful activity. I am always shocked by how quickly people become defensive. Similar to the Oprah Winfrey show experiment. I would be curious to see how it would pan out in today's world. The one thing that can never be taught is the feeling of perptual inadiquacy. As white people we will always be able to avoide uncomfortable situations, we will always be able to go home and feel safe. That isn't the case for people who are discriminated against. They cannot take off a collar and get relief. Their collar is permanent. It's the people without collars that have to change.