It would be quite expensive for the Russian government to poison everyone who ever went to a protest, or who socialised with the wrong sort of people. Also, if

It would be quite expensive for the Russian government to poison everyone who ever went to a protest, or who socialised with the wrong sort of people. Also, if it's cheap enough, the government can apply low-level incentives/nudges at the top of the dissent "recruitment funnel" as well as high-level high-profile actions against the few brave people who make it all the way to becoming leaders of these groups.