Why can't they just break up the crime and let everyone go?

The main contention in this film is that we can't arrest people who commit no crime. But why do they need to arrest them at all (and inhumanely imprison them inside that vault to boot)? Can't they just break up the crime in progress, give everyone a warning, and call it a day? Cops in our universe do this all the time, and they would LOVE to have a system like this that would tell them when and where a crime is occurring. If the goal is to stop a crime from occurring and save the life of a potential victim, then the pre-crime system in the movie should work fine, minus the arrest and imprisonment. Sci-fi stories often paint a dark picture of new advances causing more harm than good. But maybe the trick is finding *correct* implementation of those advances. Nuclear physics brought us nuclear bombs, but it also invented MRI machines that save lives.