I’ll file this under slightly plausible, but highly unlikely. My reasons:
1.) All these people that are suspected of using doubles are high-profile cases where they had been set up for a fall from the very beginning by the government. Such a scheme would require collusion from the government itself, and the government wants them to suffer.
2.) In a nation of over 10^9 people the odds of a double for yourself existing are high, but there is no good way to find a double for yourself, at least while keeping it quiet and secret.
