[meta-level]

Can anyone explain to me what keeps anyone who doesn't want to be monitored from just sending PNGs (or similar) containing messages encrypted in each pixels LSBs?

Doesn't all that just force everyone who has something to hide to use something else, less obvious?

[1gn15]

Probably friction. Will you be able to convince your friends to do that?

[meta-level]

No, probably not - but those bad guys with all their child porn and terrorist plans won't mind the friction (those will either encrypt or become EU politicians).

[happyopossum]

Presumably the distribution of an app that facilitates that would become illegal as well.

[hellojesus]

But would that actually stop people? I can say with certainty a law such as this would encourage me to go out of my way to create and distribute such software.