As I understand it, labeling the contents is a stipulation of the Law, "The Lacey Act". Never mind Fed Ex policy.

If someone ever opens one of my packages without my consent, they'd better prey to whatever God they believe in, that I don't get my hands on them! I don't believe it's legal, unless they're actual postal service investigators, or law enforcement officials WITH a search warrant. Otherwise it's illegal search and seizure, or illegal tampering at a minimum. It's in the constitution! I may be wrong. But,... tampering with one of my packages by a FedEx employee, or anyone else for that matter, without a search warrant, and without my consent, ever, would activate my own personal launch sequence! I can't even begin to describe the resulting pain.

The maximum effective range of an excuse is ZERO METERS!

Humor me,...What excuse or "reason" did they give for opening that package?