Most often the business hires a security contractor to take care of it, and signs the contract without understanding the terms. You should be able to trust your suppliers enough that you can do the above, they are the experts in the thing (cameras in this thing, but could be things like plumbing or accounting) and you have your own business to run. "Should" is key though, all too often someone doesn't do right by their clients.

>Most often the business hires a security contractor to take care of it, and signs the contract without understanding the terms.

The bulk of the responsibility here would lie on whoever signed I think. It's one thing to click "I agree" when you are making a SaaS account for downloading cat videos. But at a job, you are getting paid to read these things and to make informed decisions.