A:
I think LG did a great job at preventing it. If you have a static image on-screen for an extended period of time, the display will move the image around for you. It looks like it's jittering until you move the image. I believe it's kind of like a burn-in preventer.
Same thing happens when a static image of extreme white is on-screen. To prevent OLED decay it slowly starts to dim the image.
I haven't had my set for long enough to tell you, but I haven't read anywhere that owners have had problems yet.
However, the TV sets are new still and even early adopters probably don't have that many use hours out of them.
You're best bed is to check a Best Buy and turn off the floor model. That thing is on 24/7.