Info on a movie, please

Can any of the teeming millions help me find information on a movie about the fake border that the Communists in Czechoslovakia put up after they took power? I don’t know the name of it, when it was made, or anything else. I saw it on TV years ago.

By way of background, the Communists in Czechoslovakia actually built (and operated for years) a false border within their borders. They made it challenging but not impossible to pass through and set up false western watch stations (or whatever you’d call them) on the other side to attract and intercept the refugees, who would then be thoroughly debriefed by personnel dressed as Americans, West Germans, or whatever. The goal was to pump the refugees for information on underground defection networks. If any defector had military or political information, then so much the better from the Communists’ counterintelligence viewpoint. The debriefed refugees would then be turned back to the Czechs by the false westerners with a big show of cruelty. It was inevitable and actually desirable that refugee tales of how cruel and ungrateful the (psuedo-)westerners were, demoralizing and discouraging anyone who had thoughts of goign west. I don’t know how the scam was discovered and revealed, or when it was shut down.

Dunno if the Internet Movie Database will help if you don’t know the title, but it’s worth a shot.

Maybe the Wednesday night group has some ideas.