How do you know the other end of that cable is a mouse unless you dissect the mouse first? How do you know the other end isn't flash storage? How do you know i

How do you know the other end of that cable is a mouse unless you dissect the mouse first? How do you know the other end isn't flash storage? How do you know it isn't a USB hub with a flash device also connected so you'll never notice the mouse doesn't work? What if the mouse is set up to present flash storage with auto run only after it has been connected and left idle for at least a few hours? USB is not often exploited... but that just means we currently have few defenses and little for security in place which becomes a concern if we start connecting our homes with it. And to other homes. And businesses.