While I appreciate the aspects of (A) requiring physical rather than remote access and (B) the intrinsic "paper trail"... As others have pointed out, the trust

While I appreciate the aspects of (A) requiring physical rather than remote access and (B) the intrinsic "paper trail"... As others have pointed out, the trust and revocation problem of a Master Key still remains, and the device could easily be "lost" so that you can't tell the Master Key was abused. If we accept that a back-door must exist (if!) then it would be far better to have a unique key baked into every single device at manufacture-time: 1. It tightens the "need to know" since a prosecutor with a warrant only needs the one key corresponding to the device they actually seized, not a skeleton key for all things everywhere. 2. It creates a stronger paper-trail against abuse, since requests for a bajillion keys might get noticed. 3. Hackers would need to copy entire databases, instead of exfiltrating a much smaller amount of information, making it a little easier to detect. 4. It impairs any mass remote exploit, since the exploit code would need to include the keys of every possible device it would encounter and want to compromise.