
I really do not see the problem in publishing the registration number, surely this is the dogs "personal number" that identifies each dog from the others(there could be very similar names about).
Surely the problem is not publishing the reg.number but how the online registration system works? (or whole registration system?)
In Finland we have public database where you can see everything from to show results of each dog, pedigree, siblings, offspring and their results, chip number (all dogs must be chipped to be registered).
Even reason of death is recorder after the dog dies(if owner provides it).
You can also search by a breeder and on one screen get all health results of all litters they have bred, same with individual dogs - with one click you can get health data off all offspring of a dog.
You can do trial pedigrees by finding your bitch and then entering the dogs reg number in a field and you have it, pedigree the puppies would have including inbreeding coefficients etc.
I think this database is great and very useful, I wish UK KC would do something similar!