What I think watch-er is referring to is a "brokerage" system that has grown up around the Patek trade. Quite a few ADs have too many Pateks on hand and can't move them, so no turnover, no money and no new Pateks, or whatever else the dealer sells.
Along comes a broker with a buyer. He gets the dealer to sell him a piece at a substantial discount, maybe at cost, and gets the dealer to stamp the piece as sold to a "straw man". The "straw man" gives the watch to the broker who turns around and sells the watch as used (and unworn), with a legitimate dealer stamp, to his buyer-still at a discount the buyer could not get because he doesn't know where to look. I am pretty sure this would all be legitimate and Patek would honor the warranty, at least anywhere but here in the U.S.-which is illegal as has been pointed out above.