That is scary!
The UKC is considered by AKC to be a reputable registry, so if true, that's a big problem. Cole is registered with both AKC and UKC but was registered with the AKC first via the breeder. I needed to register him with the UKC because I showed him to his CH with them as well.
The UKC does require proof of parentage via UKC or AKC (or other UKC accepted registries) to register with them. You have to have the parents registration numbers and a 3 generation pedigree from that registry.
There are many breeds that the UKC recognizes that the AKC does not. Those wouldn't be able to be registered with the AKC because they're not an accepted AKC breed. Those breeds have their own organizations or associations, such as the American Bulldog Association. Some have recently been accepted into the AKC as well, like the Neopolitan Mastiff, and Leonberger. They've been accepted into the UKC for a long time.
Here are the All Breed Registries that the UKC approves:
AKC
BKC (Bermuda Kennel Club)
CKC (Canadian Kennel Club)
FCI (International)
FDSB (Field Dog Stud Book)
NAVHDA (North American Versatile Hunting Dog Assn)
TKC (The Kennel Club - United Kingdom)
I can see there might be an issue with those from the FDSB and the NAVHDA, although those registries are very old and as far as the FDSB goes, any champions and runner up champions must be DNA tested.
So it looks like to get into the AKC from one of those (if the dog doesn't have AKC lineage), one would have to register with them (needing at least a 3 gen pedigree to do so), and then with the UKC (also needing a pedigree to do so), and then with the AKC.
That's a lot to go through to get a bad dog registered with the AKC.
I'm sure it can be and has been done, but most of the breeders you see on these sites who register with the CKC (Continental), or APR, have no history on the dog's lineage, so can't prove a thing. OR they're suspended or banned from the AKC for breaking the rules. The Continental KC and APR register "hybrids" (read: mutts)....the others don't. They're puppy mill or BYB registries. You also see some pets in pet stores coming from them......but you also see pets in pet stores that are AKC registered.
So, remember, just because a dog is AKC registered, doesn't mean it's a quality dog from a quality breeder. It can also come from a puppy mill through a broker like the Hunte Corp. Our Addie Mae is a Hunte Corp/puppy mill dog, and is AKC registered...full registration too!
The best method for finding a puppy is to go to the national breed club (for Newfs it's the NCA...Newfoundland Club of America) and go to the Breeder's page. Then (after doing all your research about what constitutes a good breeder, seeing the lines you're interested in at shows, or other breed events...or AKC events), call and start talking to them. See if you "click", do your research on OFA for clearances, and take your time.