If you're a diplomat, you're exempt from all customs stuff.. clearance, only stuff covered by certain levels of clearance are covered, but not all your stuff.. Lawyer.. good luck. You can claim lawyer/client, but the CBP can still look at it. They are bound to not disclose what they see.

There was a lawyer in another thread that talked about this when dealing with TSA. TSA have the same rules. You can claim client priviledge, but most of the time that will just cost you a flight. They can search most anything, and are held to high confidentiality standards.