What the heck are you talking about?
There are 2 balls that are set where they need to go, which is almost 25% of the balls in a game of 9 ball. Beyond that, pick up the balls and place them in the rack without looking at them or maneuvering them where you want them.
It is very easy to detect. You just have to watch if a player picks up a specific ball and puts it in a specific place.
I think he's trying to say that you can't really prove that someone didn't put them where they are "randomly". Can't the same couple of balls randomly end up in the same spots? If your opponent wants you to change the order they are in, then they aren't random either. I also think it's a stupid rule that needs to go away.