You've now forced spammers to purchase webcams. And write code or whatever to make realistic mouse movements. This is expensive. Whatever they're doing likely isn't worth it anymore.
I don't get why you'd need a physical robot arm? Just have a usb device that simulates the mouse movements. Or just software to move the mouse virtually.
You don’t, you wouldn’t even need a webcam, you could just splice into the video signal at output and interpret it directly (much as the HDCP bypasses do).