[serf]

>how they can know?

Who cares,

a) it's not really worth the risk of participating, let alone participating and then knowingly breaking rules,

and b) no single person can ever have a good enough knowledge of the security systems of a state-level actor that they can confidently say that they aren't at risk.

if it were me i'd be hesitant to take the risk of personally traveling there, let alone breaking their rules.