Yes, we were afraid of repercussions, but "imprisonment or worse" seems like the same stereotype we had with Americans all walking with guns on the street like it's a western movie, smoking Malboro and listening to rock music.
The repercussions were social mostly, your boss would not promote you anymore, your neighbours would avoid you. Only in cases of high-treason, such as Assange from WikiLeaks, you would get "imprisonment or worse". Think to how PC culture works in the US. If you're misoginistic, your friends will start avoiding you, you might even get fired.
And no, people did not learn through state-approved knowledge, we had conspiracy theories, we had friends, uncles and friends having friends working inside the government.