When you put up a "yard sale" sign, you're conveying what is called an "implied license" to access the property. The scope of a trespasser's right to access a property is limited to what a reasonable person would consider to be granted by the license. A reasonable person would assume that a "yard sale" sign grants a license to access the yard on which the sign is posted, but not to go around to the back yard and peek into the basement windows.
A public web page is no different. A reasonable person would not assume that content you can only get to by editing a URL manually is supposed to be accessible to the public. A typical person would not even know that you can do that. Those typical people are the ones that get to set the rules, not hackers.
If a url is not supposed to be edited by people, address bars wouldn't be text fields. It wasn't long ago that one of the primary ways of going to a website or even a particular webpage was entering it manually in the address bar as opposed to going to google first.
Websites are not only meant to be accessed by humans either. Are you telling me that bots should employ human reason to guess what should be viewed or not?
I'm not even sure what you're proposing. The web has always been public space.
If a website puts a link to a resource that is not protected by authentication means, and hides it behind some other html element, or styles it with javascript to a white font on a white background, or does something else that is similarly difficult for a script to guess is not viewable by humans on some subset of browsers, is it now breaking the law because obviously the url was not viewable on any webpage?
How about if someone takes the url, and doesn't view it, but posts it on some other website with high traffic. Now all people that click the link have broken the law?
You are old enough to remember a world before Google, yes?
I typed http://DeltaAirlines.com into my browser's address bar, looking for info about Delta Airlines. I didn't click a link from another website or copy it from a brochure. Why is that trespassing?
> A reasonable person would not assume that content you can only get to by editing a URL manually is supposed to be accessible to the public.
A reasonable person could totally use crawlers like DownThemAll, and fail to notice that some URLs they request are not, in fact, accessible by clicking through a web page. That's different from accessing something you know isn't accessible by mainstream means.
I did that several time to download some porn. The process is simple: search for whatever I'm interested in in a search engine, click on whatever image looks interesting, see if I the URL has numbers I can modify to access nearby images (they will have hopefully the same theme, or even depict the same scene).
The first URL was clearly publicly available. I got it legitimately through a search engine, or by clicking around. How am I supposed to guess that some of the others are off limits?
A public web page is no different. A reasonable person would not assume that content you can only get to by editing a URL manually is supposed to be accessible to the public. A typical person would not even know that you can do that. Those typical people are the ones that get to set the rules, not hackers.