Paryah

And if you won't do it, the deal is off. Sometimes they want more than that! A service/code to ensure their ad is only served in X country.

"We want to advertise with you, but only in Europe, so please first pay for this service which will assure us that is the case."

And if someone isn't directly buying that inventory, there are literally hundreds of thousands of ads people might see.

Google will serve ads based on your personal browsing history. It's entirely possible YOU ALONE are seeing a specific ad on a site.

Can they be blocked? If the site knows it's being served and has sufficient information, yes. Those are assumptions.

I cannot tell you how many times I've gotten an email where someone's like "there was a girl in a swimsuit on your website please remove"

That's not actionable information. I don't know what swimsuit girl you saw. What am I supposed to do about swimsuit girl?

And I want to reiterate: Almost no websites have ads where the money goes directly from the advertiser to the website.