[tcldr]

With a warrant from a judge people should be compelled to provide access to their encrypted files or be in contempt of court with all that entails. Anything else is overreach.

[schroeding]

You cannot prove the absence of e.g. a Veracrypt hidden volume or similar, though. Even if you honestly give up your key, you could still be either

A) held in contempt of court, if the authorities do not find what they expect for some reason and accuse you of using such techniques or

B) if you specify that such behaviour by law enforcement is overreach, have a clean way out for criminals, codified in law, heavily damaging the impact you may expect of such a law.

[Y_Y]

What's the difference between that and an incriminating paper document that the police believe you have hidden somewhere in the vast woods?

[heikkilevanto]

Wonderful idea. All I need to is to create an encrypted file with pedo pictures or terrorist plans or just white noise, send a copy to all my enemies, and tip off the authorities.

[boxed]

And what happens when your enemies can't produce the decryption key?

[fauigerzigerk]

No, that's not all you need to do unless your only goal is to harass your enemies and cause inconvenience.

[jdasdf]

No one should be compelled to aid in their prosecution.