When I'm arguing against the idea that someone can own ideas, I usually use either cars or chairs as an example. If you buy a car, I say, then you own the car, and the car company doesn't try to restrict what you do with your own car in any IP sense: you can sell it to someone else, take it apart and modify it, rent it to people, or whatever you want, because it's none of the seller's business. Apparently, however, the car companies (well, Ford, at least) have been paying attention to the logical conclusions of the IP debate, because now they're claiming that pictures you take of your Ford-built car are their property.