Every networked sensor package in your immediate vicinity can be used to spy on you unless it is well-designed and transparent to you and the wide community of security researchers. If that sounds paranoid, check out the video above, wherein some security researchers show that they can covertly operate WiFi-enabled personal cameras and turn them into bugs.
But, as proven by Daniel Mende and Pascal Turbing, security researchers with German-based IT consulting firm ERNW, these capabilities also have security flaws that can be easily exploited for turning these cameras into spying devices.
Mende and Turbing chose to compromise Canon's EOS-1D X DSLR camera an exploit each of the four ways it can communicate with a network. Not only have they been able to hijack the information sent from the camera, but have also managed to gain complete control of it.
In this presentation from Shmoocon 2013, they explained in detail how they managed to mount the attacks, and have also offered advice for users on how to secure their cameras and connections against these and similar attacks.
Stuff like this is why DRM and EULAs are so insidious. The existence of devices that attack their owners affects us all. It is a public health problem. Any time we pass a law that makes it illegal or legally perilous to point out flaws in technology, we make it harder to solve the public health problem, and we're all at risk.