>the cost to Apple would be incalculable.

the same statement about "not providing direct access" will get them off easily like it already did for them and Google/FB/etc in case of the rest of personal information.

I'd say it would be negligent on the part of NSA to not use such a convenient source of fingerprints of "foreign" persons :)

>at least hope, that Apple has designed the hardware involved to be subpoena proof

why would a corporation intentionally do it? Conspiracy of obstruction of [future] justice comes to mind.