I bought mine through the online store. The Apple Store wanted to keep the laptop for a week to replace the screen but I'm in school and cannot part with it for a week, so they sent me an advance replacement. If it's doing IR out of the box like mine did, I'd schedule an appointment with a genius, and while you're waiting, set your background as light grey and just leave a website up or whatever. Then minimize it when they ask what's wrong and show them the problem. It's not acceptable for the price.
People are saying not all LG's have IR, but I call BS. I find it hard to believe that "only a batch" of screens have the problem, and somehow this batch is still being distributed. Anyways, good luck.