Activists typically aren't secretive about their actions, on the contrary they tend to be as public as they can safely be. The setup though might be, if it's to prepare an event that might be crushed down before it even take place, but then even a day later, not even a decade, to decipher would be too late and thus pointless.

That’s not a message activists tend to care about though. In places where speech is dangerous enough for this to matter, there are usually far more immediate threats.