Production cost in one location vs near-new cost in another perhaps? If you can produce one new in X for $1k, and sell a near-new one in Y for $2k, you might as

Production cost in one location vs near-new cost in another perhaps? If you can produce one new in X for $1k, and sell a near-new one in Y for $2k, you might as well make cash on the shipping by carrying goods (if it has to travel to Y anyway, it's going to get beaten up in transit whether it's full or not).