Cameras don't prevent crime. They don't prevent accidents. They're at most used to find afterwards what happened.
By the time a cop would decide to bother and check the cameras, and find you in the footage, and trace your steps through the various cameras, you would have been back on your own already.
The ideas that cameras are a matter of security for the people is propaganda. They are here to destroy privacy and allow the elimination of opponents and dissidents, they don't really care about crime. Doesn't mean that cops would never use them for other purposes, but they definitely don't care as much as you think. And of course, caring isn't the same thing as being able to do anything in a reasonable time.
No.