The mega rich guy is the only one who hasn't. I think that they are told to do so by the producers, and it looked liked he had changed his mind, because from what I remember he did have a suit carrier with him when he arrived.
Although I didn't warm to the guy this week as much as some others, I think some posters are being harsh. He has only recently come into money and doesn't have the same riches as Nick (much as I liked him) does.
There's a programme on this week going back over previous shows seeing how the Millionaires have changed lives/kept in touch.