How secure are wireless mice?
Is it possible to control a wireless mouse from a different computer?
Is it possible to know the mouse movements from a different computer?
From testing, I have demonstrated to clients that yes, both of these are possible. The machines are supposed to have a 1 to 1 relationship with the mouse, but for some types of mouse there aren't a lot of ID codes, so you can get overlap.
The same is true for some wireless keyboards.
Simplest solution: if you are worried at all, use wired devices