I found this little question on Facebook asking if there was a way to stop the mouse moving over to the projector or other secondary display. After a quick google i found the application Cursor Lock, Cursor Lock will lock your mouse to the Propresenter operator screen so that the operator cannot accidentally put the mouse on the public facing display.
you can find the application at http://www.snakebytestudios.com/projects/apps/cursor-lock/
you Will need to install .net framework 3.5 to get it working.