Buying a house is usually an impersonal transaction. The buyer sees a scrubbed version of the home, artfully “staged,” possibly with a fresh coat of paint and flowers on the table. Once a purchase price has been negotiated, the buyer and the seller sign legal papers in triplicate, and the new owner gets a set of keys and – if lucky – an extra garage door opener. So, when Hal and Corinne Prewitt decided to buy Mitt and Ann Romney’s Park City, Utah home in spring of 2009, they figured they were in for another paperwork hassle. What they got,...