Making use of encryption...
...requires some care and forethought.
If you can ensure that you never have access to the key, then it is impossible for you to give it up on request, Hence you need ephemeral keys and get perfect forward secrecy.
Now, that takes care of the interception problem, you can't render intercepted material intelligible because you never had the session key, only the server knew it.
Now you have the problem of storing what you receive. You need to memorise simple information and then securely delete it. When Plod comes to call, all he gets is...nothing. He can't compel you to decrypt non-existent material and he can't recover securely deleted email. Of course, this means you need to run your own mail servers, but that's not too hard these days.
So, while this sort of behaviour can be seen to be suspicious, nothing can be proven.
If only we could get enough people doing this, but then eventually fear of fraud and identity theft is going to lead to all links being encrypted in transit at which point interception becomes very much more difficult or even totally useless.