>Yes, but it doesn't cost money to view the network's history, which is analogous to purchasing a security camera.

It works if you assume everyone who purchases a security camera makes their video feed/history publicly available for free.

But then only one person would need to buy the cameras, so why mention it?

If only one person has a security camera, his buddy can go in the room and mess with the money, and he can splice in fake footage so no one finds out.