The one piece weight will not come off if it is the correct weight. There are about a dozen different weight types. It is very typical for the tire stores to use the wrong one and see it come off. If the correct one piece weight is used, there is still a down side, it will scratch the wheel, where the two piece weight if applied correctly will not.
The two piece weight is not exclusive to the MB dealer. They are available after market, but not all tire stores have them.
Also "high speed computer balancers" are not exclusive to the MB dealer. They are EVERYWHERE. The difference is the operator and mainly the operators attitude.