>> This way you comply with their implicit wish not to have you read their content without some sort of monetary return.

I make no promises about the way I'm going to render your site when I request data. I'm just requesting some data from the server.

I might be reading it in lynx, or over a slow connection with images turned off, or on an ancient browser, or whatever.

I prefer explicit to implicit - if you wish to enforce my rendering method, you shouldn't give me the data. I would even be happy with sending a flag in my request - XWillNotRender or whatever, so that you can filter me out easily if you wish. But once I have the data my device can show it to me however I wish.