Prisons operate by setting up different areas, marking them with custom flags, and then assigning specific functions to those areas. For instance, there’s an area for isolated confinement, another for the mess hall, and then another for the exercise yard. This kind of division in the prison makes things easier to control. This is especially useful when a prison riot takes place.
After all, you wouldn’t want anyone to get hurt or for an inmate to break free. Instead of dealing with everything as a whole, the security force there can easily lock down different areas and contain the situation efficiently without involving other areas.
Security observation posts surround the common grounds. This is because the only way to keep everyone safe, they have to continuously keep watch over the prisoners. And since common time is the most dangerous time, the security force has to be at their most vigilant. They usually set up different blank flags around different areas. This usually means that certain people are not allowed to enter specific areas. This usually minimizes conflicts that could spark from there.
The most important thing for security forces to realize is that if something happens, they could lose their lives trying to stop the prisoners. In fact, there have been cases of members of the security force not making it out of riots and other disturbances. Since they died in service, their police departments hang police mourning flags outside to honor their memory.