"(3) A dedicated encrypted criminal communication device does not include-- (a) a device if-- (i) the device has been designed, modified or equipped with software or security features, and (ii) a reasonable person would consider the software or security features have been applied for a primary purpose other than facilitating communication between persons involved in criminal activity to defeat law enforcement detection,"
It's not automatic: depending on what a reasonable person thinks and the definition of criminal activity.
Does the jurisdiction matter? For example, if an activist was using a device to do things in another country that would be legal in Australia but were crimes in the other country.
So "the government only considers a duress PIN illegal if it is used to facilitate crime" seems like a potentially tricky standard to apply.
But this is just legal fiction, so not a barrier to "automatic"