Lol,that may have been true 20 years ago,but not anymore..Even back when I used to go to every show I would see the same dealers with the same overpriced crap year after year.
Yes, those are the dealers who won't negotiate and would rather carry the stuff they paid too much for around from show to show. Its worth mentioning it to them though in your negotiation, tell them you've seen they still have this and you looked at it at show XYZ and how about taking this much to stop hauling it around. Costs you nothing to try.