I had a similar incident in PC World yesterday. I saw a monitor I quite liked, on the way to the till, I noticed that on the clearance table they had exactly the same monitor but unboxed with a sticker saying 'At least 40% discount'. I took the unboxed to the till to find it was the same price as the boxed one. Despite a chat with the Manager, there was no further reduction so I left without either.
Chris
This is a common trick at my PC World. They fill their so-called clearance area with stuff off the shelves at the normal prices.