What's the difference between encrypted messages and broadcasting random noise? Who could actually prove otherwise without the key?
If they claim is not encrypted it's just noise, prosecute them for broadcasting noise.
If they claim it's not noise it's just encrypted, prosecute them for broadcasting an encrypted signal.
What do you think the practical difference in outcome is?
We both have a shared key, I send you a cat picture over ham radio with the message encoded in the least significant bit of each pixel.
How exactly is that going to be detected? The picture looks virtually the same as the original.
Not everything is about whether or not you get caught.