I don´t know how many top foreign communists were asked to visit Moscow by Stalin or the Party in the 1930´s but anyway several of them never returned, I know many Finns never came back and also several Polish ones.

the Finnish communists knew what would happen to them because " a true communist did not live outside USSR" in Stalin´s view, they were spies or the sort. Some kinda reason to send them to Gulag anyway. So they decided if not take part in Winter War at least not interfere by causing sabotage.

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