> You bought that pizza, and you own it. Period. When you go to a website, you are not buying or owning anything. You are requesting a set of data and refusing the price that comes along with it.

I bought my computer and my internet access. I then sent a request to another computer on the internet, and the owner of the other computer had every right to instruct the computer to either deny or fulfill my request. The request is explicit and the successful response is explicit, without any condition that I go on to make other requests that may be described in the response body. These network interactions are well-specified and explicit. The computer fulfilled my request, period, and I have no reason to believe the computer was unintentionally programmed to fulfill my request. I am fairly certain I have violated no laws (unlike your poor analogy to trespassing), and even more certain that I have no moral qualms over my actions.

To say that my initial request for an HTML document constitutes an agreement on my part to parse the response body and make all subsequent requests and execute all code described within (recursively, perhaps) is frankly ludicrous. The response body could contain descriptions of requests for unwanted, offensive, dangerous, or even illegal content. It is ridiculous to claim that I have agreed to these things, especially when I couldn't possibly know what I was "implicitly agreeing" to.