I was fortunate enough to encounter Sehgal’s work while living in the UK for the past couple of years. In particular, ‘This is Propaganda’ was included in the last Tate Triennial and I visited his shows at the ICA, which recently hosted a series of Sehgal exhibitions over the three years - the last of which I have reviewed here: http://makingsensesofitall.blogspot.com/2007/03/art-tino-sehgal.html

Sehgal’s work remains innovative and provocative. He possibly represents the most promising and stimulating future for the amorphous movement tagged Relational Aesthetics. He brings together in one single conversation many of the prickliest conundrums surfacing and re-surfacing contemporary aesthetics and the most practical concerns for a breed of art that engages its public more fully. Possibilities abound!

Additionally, it might be interesting to note that according to an AP report interviewing Sara Macdonald, the spokesperson for White Cube, London (Hirst’s gallery), "Hirst retained a stake in the work. She would not give details on the size of his stake but said he would sell his share when the piece is next put up for sale." So essentially he has sold the work to himself and probably his dealer Jay Jopling. You or I could make an artwork and price it for $100 million, or a billion as you note, all that requires is a price tag and magic marker, but the important thing is selling it. Hirst has “sold” it, it wouldn’t look good otherwise and his October auction prices were pretty lackluster. Follow the money, because this piece is more money and market than true art.