More generally, do you have to legally agree to Terms and Conditions to communicate with service provider's servers over HTTPS? Do you legally agree to them after you communicate one packet in such a way?
I don't think when Google crawls various websites, that Google has to agree to various licenses those website owners may have, or that its crawling of them implies such agreement.
It's ridiculous to believe that a magazine publisher, or a TV provider can require users to watch or hear the ads. Real life shows many people intentionally don't, using various methods, and I see no reason why Youtube provider should be different in this.