I agree. You should always know when a camera is on. When webcams first started, they had a physical cover so that people could know that the camera could not see them. I guess that went away at some point.
The lack of an LED is inexcusable. PC hackers have found hardwired LEDs on webcams to be a frustratingly difficult to defeat security measure - This is a good thing!
I realize that the television manufacturers are using the cameras as part of their UI and that they don't want to creep people out by letting them know that their TV is watching them, but that is their problem. Even the Kinect on my xbox lets me know when it is looking at me.