Right--a common-carrier delivery service, like UPS, DHL, or FedEx, only they cannot snoop into the clients' private business, and clients are by design anonymous.
Yeah, but if they are aware of the "type-of-content-that-may-be-in-the-box" can be illegal or inappropriate. It's still their fault to deliver.
This doesn't stop police from raiding them.
Common-carrier delivery service, like UPS, DHL, or FedEx are "aware of the "`type-of-content-that-may-be-in-the-box'." They are not held responsible for the actions of their clients of which they are unaware. The same holds true for telephone companies, Internet backbone providers, Internet service providers, and more. The same should hold true of Tor exit node operators.