Just because having a boom in the scene is easy to explain doesn't mean it is any less unprofessional to keep it there or to not take it out in postproduction.
The boom problem can be easily narrowed down to two people. The cameraman and the boom operator. The cameraman should be constantly watching for the boom as the boom operator needs to keep the microphone as close to the source of the voice as possible to eliminate bass proximity effect (for information on what bass proximity effect is, please e-mail me).
Correct me If I'm wrong Ron, But the finished product should go to the projectionist. In other words, Cropping should be done with the production before it goes out to the theaters.
Actually, the projectionist is responsible for framing the film correctly. This means that they are responsible for blocking out portions of the top and bottom of the picture. When the film is made it is made with all sorts of extraneous stuff in the picture with the knowledge that it is to be framed at the theater. This is very common and is frequently the reason you see boom mikes in the tops of shots.