The point is I know from casino and life experience that when a dealer is taught how to spin they are taught to get it in a area when needed. Lets say you and 5 other high rollers are at the table and most of the bets are on tier, then the spinner is going to be spinning in the 0 area where there are not as much bets (which is easy for them).
It also works the other way. If you find a bored croupier and tip him well enough you can see some impressive stuff.