I don't see anywhere that states the LG operates a 50Hz, shouldn't it be 60Hz?
The HDTV is advertised to have an average response time of 5ms. Generally speaking, all LCD monitors will have ghosting issues from time to time. It's just the limitation of LCD tech.
Watching sport events on an HDTV will give you something worse than ghosting from time to time. It's called pixelation where parts of the screen will have slightly "blocky" images. This is not the fault of HDTVs, but the fact that the video is compressed on the fly so that it does not take up an excessive amount of bandwidth.
Pixelation will occur when there is a lot of action in the screen. The more movement the more pixelation. For example, when the camera view have several player and the crowd on screen and everyone is just standing around, everything should look fine. Then the action starts and the camera zooms and starts following the player with the audience in the background. That is a lot of movement on the screen because the players are chasing the ball and the crowd is gesturing and cheering all while the camera is moving around... Pixellation City.