Banksy said this in relation to billboard type ads but it applies to online advertising too. Is there an acceptable rock you would allow someone to throw at your head?

>Fuck that. Any advert in a public space that gives you no choice whether you see it or not is yours. It’s yours to take, re-arrange and re-use. You can do whatever you like with it. Asking for permission is like asking to keep a rock someone just threw at your head.