To be allowed to leave you had to sign a paper promising to "tell" the secret service on your travel companions after the trip. So everybody on the trip was living in paranoia of one another.
It was mostly to later have some blackmail material on you if you became opposition - you signed the paper so you're an agent of the system.
And when (if) you returned - regular people assumed you have some connections to the regime and treated you like an enemy.
To be allowed to leave you had to sign a paper promising to "tell" the secret service on your travel companions after the trip. So everybody on the trip was living in paranoia of one another.
It was mostly to later have some blackmail material on you if you became opposition - you signed the paper so you're an agent of the system.
And when (if) you returned - regular people assumed you have some connections to the regime and treated you like an enemy.