It is important to realize that the evidence monitors are like multiple computer monitors on a single system. If a user presses the pointer tool button, all evidence monitors will have the pointer tool selected. Any action on any evidence monitor affects all the monitors in the courtroom.
Discretion should be employed and pressing buttons on the evidence monitor should be limited to times when no one else is actively using the annotation tools.
The following video shows that when other parties make annotations on the monitor, it will show up in all the monitors simultaneously. Notice that the tools in the tool bar are being selected by other parties but also show up in the monitor on the screen.