I think (but am not sure) that there are long established postal laws in most territories about sending “obscene” material through the mail. I think this was used to prosecute pornography publishers in earlier times. BUT you needed to (a) intercept mail and (b) have a good reason and (c) get a warrant to open (interfere with) that mail.

Possessing pornography was a separate issue which may or may not be allowed. Typically (I think) authorities went after publishers not consumers - because they were easier targets to pin down.

Which would seem to imply that if you’re sending encrypted traffic at the request of a recipient the as a publisher of “obscene” material then unless you are delivering very clearly illegal content to a user then you should not prosecuted.

I haven’t got a single source for anything I’m saying, so I might be entirely wrong - I’m simply going off half-remembered barely-facts. So please do argue with me!