"The computer doesn't need to reject your attempts to, e.g., see other peoples' account information for you to know that's outside the scope of authorized use."

"The computer doesn't need to reject your attempts to, e.g., see other peoples' account information for you to know that's outside the scope of authorized use." Then how do you know it is outside the scope of authorized use? I can browse the white pages and get some people's phone account information, is that authorized or not? Outside of a computer, what does common sense say about what is authorized or not?