There's no need for this (anymore). You're already allowed to disclose (coarsely) the number of NSL you've received[1].
[1]: https://www.justice.gov/iso/opa/resources/366201412716018407...
> You can't force someone to say something in the US can you?
Unclear. The EFF believes you can't be compelled to lie, however you should consult an attorney with details of the specifics.