Even in China, selling used anything as New violates the law. Sure that only really works for Chinese Nationals as far as prosecuting goes but it IS excellent grounds for FTC to bar imports so. Bottom line is no they don't/can't. For warranty replacement them using reworked/repaired boards is allowed and in fact is very commonplace throughout most electronics industries.

As for getting dirty/dusty miners... Ever been to any large city in Asia? When it's dry they are often very dusty places. The miners are typically all burned in for at least 72hrs in open buildings. Dry out of the rain yes but sucking all that city air well you get the picture.