This is actually typically against the ad networks' terms of use. In all AdChoices ads, you'll see a small "X" in the corner. If you click it, one of the first

This is actually typically against the ad networks' terms of use. In all AdChoices ads, you'll see a small "X" in the corner. If you click it, one of the first options is to report the ad obscuring the content of the page. I'll admit I don't know what the result ends up being, but I'd hope that they get in touch with the implementor to tell them to fix their ad.