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.
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.