I seem to remember that back in the sweet usetobe before the internet one of the big catsup companies (Heinz? Hunts?) started suing restaurants for the common practice of watering down their catsup bottles that sat at the customer table. The catsup company was worried about people forming a negative intial impression of their product based on the watered down bottles. The restraunts argument was that once they bought the catsup bottle they were free to do what they wanted with it.

Don't know how that suit came out but this seems like the same deal here.