SUMMARY: Still trying to find specifics about the ruling. Meanwhile, here's a tidbit of background info.
Why do Rottweilers now have natural tails?
In 1999 the country of Germany passed a law that made it illegal to dock a dog's tail or crop a dog's ears. The basis for this law was the fact that the practice of docking and cropping was deemed to be inhumane treatment of animals.
In order to comply with the new law, the ADRK revised the Breed Standard for the Rottweiler and this new breed standard required a natural tail. The FCI translated and adopted the new breed standard and gave all FCI member countries several years to comply with the new breed standard.
A docked Rottweiler does not conform to the current FCI breed standard. As each FCI member country finalizes their adoption of the new breed standard Rottweiler breeders in those countries will no longer be allowed to dock and docked Rottweilers will be disqualified at shows and prohibited from breeding.
The AKC (American Kennel Club) is not a member of the FCI. AKC does not follow any of the rules and regulations set by the FCI for the rest of the world and they do not always follow the breed standards set by the countries of origin. The AKC Breed Standard for the Rottweiler has always deviated from the FCI standard and they are currently struggling to deal with the breed standard regarding the tail.
There are a number of Rottweiler breeders in the United States that follow the FCI Code of Ethics for breeding and strictly follow the FCI/ADRK Breed Standard for the Rottweiler and those breeders will all leave natural tails on their dogs.
(Read the rest of the article, including more position statements on tail docking in general and in Rotties in particular.)