[declan]

NSLs are likely not the case here with Yahoo (and in fact are not the most significant privacy threat, IMHO). An NSL is a demand from the FBI, not a court order. NSLs also have unique First Amendment vulnerabilities that would help a company choosing to publicize receiving one.

A FISA court order, which can force you to do much more than NSLs, is the more significant operational threat to Internet companies. These court orders typically have "do not disclose" provisions. Willfully violating that court order will almost certainly result in contempt charges.

[malandrew]

What if you had all your mail scanned or OCRed to remove certain phrases such as "do not disclose" and then the resulting message was delivered to you.

The key here being that you will never have any knowledge of such requirements and therefore cannot act with intent to violate such requirements. Basically, can you eliminate mens rea as an element of the crime of contempt?

The burden is on the deliverer to make sure you receive, open, read and acknowledge the entire message instead of a partial message.

[dragonwriter]

> What if you had all your mail scanned or OCRed to remove certain phrases such as "do not disclose" and then the resulting message was delivered to you.

Willful blindness is (as one might expect) evidence of willfulness of an act, rather than a way of displaying an absence of willfulness.