I can’t say I know what the quip about the roast duck is supposed to mean. I get my wisdom from fortune cookies. Fooling foreigners can be pretty lucrative. Decades ago in Shanghai well before the skyscrapers went up there were people selling fake antiques on the sidewalks. They would take a department store vase and boil it in black tea for sometime until it’s stained and little cracks appear on the porcelain making it look like someone had dug it up last week. I doubt it was a coincidence they are often seen half a block away from the tourist hotels. People actually fell for that.