I have the same problem as mentioned in the first post. Also, I've have it only once with the pattern unlock enabled, so there was combination of power on key that turned display on and wrong gesture for several times. The problem is that phone then asks for PIN and it will automatically *disable* knock or pattern unlock, so you need to set it again...
It is a good feature but most of the user will disable it. Maybe LG do something in some of software updates. BTW, why still there is no update for him? There is ton of bugs.
Samsung Galaxy S3