The difference, in the PJ ethics sense of things, is that while the car is gone in both cases, cropping is a "lie of omission" while cloning is a "lie of commission". It's the difference between not mentioning the years 2001 through 2003 on your CV at all on the one hand and claiming you were the CEO of a now-defunct foreign company (when you were actually incarcerated) during that period on the other. (That's a bit hyperbolic, of course, but such exaggerations are differences of degree, not kind.) All journalism, no matter how "fair and balanced" you wish to paint it, is editorial and bias, but there is a big difference between editorial and fabrication. (And you don't have to zoom or "zoom with your feet" normally; cropping in post/printing is ordinarily allowed, though the editor/publisher will want to see the full frame as well. The shot you intend is not necessarily possible with the lens you have mounted - think of all of the PJ that has been done with wide primes over the years, as often as not so that "f/8 and be there" is all you need to think about. As long as the full frame is not showing your crop to be a blatant lie, like turning a dozen people in an otherwise empty city square into a massive popular demonstration, the publication will usually run with the image you intended rather than the one you captured.)