A girl after having a talk to her parents in which she had been showing them her apartment via the web-cam, left the web-cam on accidentally.
Read below what happened then:
#1 The girl after speaking to her parents forgot to shut the web-cam.
#2 She then moved doing some other stuffs and the camera was silently recording everything
#3 She even had some phone calls and even once realized that something was wrong with the laptop, but couldn’t find what.
#4 And then what got recorded was really very ‘disturbing’.
Fortunately, the above showing examples are not the exact of the girl but is a movie, but it perhaps explains what could happen if your web-cam left on.