I believe the problem where people's track pad makes the mouse skip around is because of the charger. Something is wrong with it, there's a design flaw and somehow a small amount of the current is going through the laptop and you need to earth yourself to stop the current passing through the track pad to not distort your mouse movements. It's funny, sometimes it happens alone, but when it doesn't, I can replicate the issue by holding my iPhone while it's charging, then touch the mouse pad.

Just an FYI. I might be wrong.. though I feel quite certain the trackpad is fine, it's the charger causing the problem.