If I was a betting man (and I am
) I would put money that it's just as Camkid54 said. They put these on as an easy temp fix. They'll get a fixed Brembo caliper in and start putting them on cars then. It'll be a recall for the ones with the weights on the calipers to come get replaced.
It's not a safety problem. In fact, I will probably just leave mine with the weights. It won't bother me at all.