As another user mentioned, I think the safest way to do this in the scenario you described would be to establish a code where innocous sentences have a certain meaning attached to them in advance, but that of course would require the hypothetical person to be prepared/expecting imprisonment.
Another thing I can think of would be smuggling a small phone in the ass or another orifice, but that would be a lot more risky, as it'd be likely that they'd check every square millimeter of the person's body and being caught probably wouldn't end well.
Well, I think that it would be if not impossible, then extremely difficult to do that, as the amount of people they'd have to catch would be gigantic.
But I think it's best to be prepared for a lot of social media bans and restrictions. (Think China or Saudi Arabia)
And if you happen to partake in protests, do NOT confess to it online. This is especially important if you're doing anything illegal, but looking at what the situation is over there, I'd say that it applies to peaceful protesting as well. Take care.
Depends on the cereal. If müsli or granola counts, and you're allowed to eat it with milk, you probably could live like that. (source: I have lived 4-6 years eating mostly granola)
Ok I looked into mercury and it might be what I'm looking for. Any idea how long it'd take before the effects become noticeable?