Hm, it doesn't cost any money to gain access to the network though. Anyone can download the client.

I think the point is that mining costs a little bit of money in electricity, and mining is more effective the more money you put into it.

Yes, but it doesn't cost money to view the network's history.

To stay true to the analogy, I would include lottery tickets. However, I don't think this is necessary. The core concepts are explained.

>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.

If you want to stretch the analogy (you shouldn't) you should say a camera requires batteries to run.

Hey that's a clever idea. I love it.