Ummm, the original post had nothing to do with the factory defects. Had to do with a pair that was clearly tried on, lace bag ripped off, and looked like someone had taken his shoe paper, balled it up and was shooting into the trash as if the stock boy had some makeshift bball game in the back (I'm clearly being facetious). And I don't know where you live, but I can guarantee you, you ask for a discount because of the aforementioned, they're gonna laugh right of the store in Houston. Then, the guy behind you is just going to buy them regardless of how nice you are. If they're some GR shoe, that may be an option for you. If they're limited, good luck with an extra pair your size to be available. I do believe Ralph had a guaranteed ticket or won a raffle. That said, if they're already accounted for, no one should have been trying them on to begin with.
Now if you're talking NDC, they at times will give you a discount. Other times they'll simple tell you to send the shoes back and get a refund. It really depends on who you get. FTL, Eastbay, FA online is the same way.