Are these little balls supposed to fall off or wear off?

I have a pair of Nike CTR360 Maestri Elite II (Firm Ground), and I was wondering if the little balls on the bottom of each stud are supposed to wear off or break off. I've seen this on previous pair of cleats but never cared. Since these cleats are carbon fiber on the bottom, I really take good care of them and was just wondering.. Please help, thanks a lot.