And unsurprisingly there are many accounts of this being abused already, heres a few high profile examples: http://en.wikipedia.org/wiki/Robbins_v._Lower_Merion_School_... , http://arstechnica.com/tech-policy/2013/03/rat-breeders-meet...
Either way thats not the point, I don't have a webcam or mic plugged in, except when i am using it for video chat or gaming, and afterwards i unplug them. The xbox's cannot be removed like my PCs.