In our local facility the other residents friends and family weren't always as honest as the residents; so stuff disappeared all the time. I had my buddy who was disabled and in a swing bed unit get one of those cable attachment locks, and use it to secure it to the desk. So one might want to buy something that has the required attachment points on the device.
Your argument is also another good idea why it may be better to use an all-in-one with a touch screen interface, so that no mouse, or keyboard is needed. Those maybe pilferable items as well!