I read this on page 157 of Edward Epstein's The Big Picture: The New Logic of Money and Power in Hollywood.
Producers may also make product-placement deals that can further delay shooting. In the case of Natural Born Killers, for example, a producer arranged for the director, Oliver Stone, and other members of the production to get two free pairs of cowboy boots in return for showing the boots' brand name, Abilene, on a passing truck. The book truck was to make its appearance by passing the open convertible driven by the character Mallory Knox in a single shot. This meant that the two vehicles . . . coming from opposite directions had to arrive in front of the camera at precisely the same time. Over and over again both drivers, starting their approach a half mile apart, had to be continually cued with walkie-talkies as the camera . . . swooped down.
I agree that film-making is an art, but all that for a pair of boots? It's incredibly petty, and you wouldn't find such a thing in higher arts, like painting and poetry. I wouldn't think so anyway, but there's a lot of junk in painting and poetry, too. If they could work a new pair of boots into their pieces, they might.