I have a computer in my bedroom. I also have cats. Unfortunately, cats and screen lockers don't mix well, particularly at night. To be accurate, it's more a problem with the display power management than the actual screen locking. Here's the way it works: I run a script to "shut the lights off at night" (that is, lock the screen and force the display to power down), and that works great, until one of the cats jumps on the desk and causes the mouse to move and turn the display back on. And the cats don't even have to touch the mouse; the slight movement of the desk is enough to cause the mouse to react. Recently, I'd had enough of it and figured there had to be a way to disable the mouse and "refactor" the script.