Punishment Park , a film by Peter Watkins .
Watkins made the film in the California desert over only a three-week period with hand-held cameras and a supposed European “news” crew. He used young antiwar protesters whom he’d met in Los Angeles, depicting themselves being summarily tried by military tribunals and then given a choice between imprisonment or completing a three-day course in one of the government’s concentration camps, called “punishment parks.” In the scenario, they all choose the Punishment Park, where they must complete a grueling course to reach the American flag without being caught by armed police, for whom this is a training exercise. Concentration camps were indeed authorized in case of a state of emergency under the Internal Security (McCarran) Act of 1950 .
After screenings at the Cannes and New York film festivals in 1971, Punishment Park was not picked up for distribution by either the US film industry or television networks. Eventually it ran in a small New York theater for four days before it was closed down. The film fared a little better in Britain
A short video of Peter Watkins describing the making of Punishment Park can be viewed here