Julian Sanchez of the Cato Institute has previously pointed out that a downside to creating an easy accesskey for the feds, is that an easy accesskey then exists and can be stolen by hackers.
As you can see in the screen shot below (from the Ars Technica article), you can provide links to your files (either containing the key so someone can access them directly or by providing them with the key separately) but you are prompted with a caution about not transmitting the keys through insecure channels and a far-reaching copyright warning.