Yes, but how I read that sentence is that Banksy is talking about the relationship between the advertiser and the one seeing the advert, not the one selling the

Yes, but how I read that sentence is that Banksy is talking about the relationship between the advertiser and the one seeing the advert, not the one selling the space to advert. _Even_ _if_ Banksy made all required agreements, he would still be severely limited regarding how he is allowed to use existing ads and e.g. communicate to the people criticism regarding the ads. I do not expect everyone to agree with his views, as this is pretty much the core of the IP discussion that has been going on for quite a long time. (And just to note, I almost kept only the first paragraph of my original comment for why people have strong feelings against ads, but decided to include also the rest for some context.)