Arthur Abrahams incisively notes:

Seems to me that there would be a certain amount of trouble with people registering one private key but communicating with another they had forgotten to register. Bad situation for my large sibling 'cause he wouldn't realize this until after the court order etc. A good solution would be BIG fines for mis-encryption and sampling of messages...

There is no need for sampling of messages. You don't understand the theory of power. Simply make the penalty for encryption without registry, larger than the penalty for any other crime. Then no crime can be hidden behind it. It's like getting Al Capone for income tax evasion; if you investigate someone and they are enforcing privacy on their communications, you can put them in jail for life for that, and can stop worrying about the original suspected offense. John