Procedures differed somewhat and a Stasi officer wouldn't have had the operational freedom depicted in the movie (that is, his colleagues very likely would have caught him).

The story is one of those unrealistic "protagonist acts against all odds and succeeds" that make up a good movie, but the backdrop (Stasi's - sometimes not very - subtle omnipresence and the fear this evokes in society) is painfully realistic.

Ah yeah, it's definitely not a documentary, sorry I was unclear. Pgeorgi has it right - I meant that it was interesting more from the standpoint of what having something like the Stasi around does to people.