The Edit access page /access.php has information on who can access the page by default. In bug #1190720 we add info when no access is given. We would have to write out more explicitely who has access to a page by default in that one sentence, but that would just get too long. Therefore, we are thinking of changing the top paragraph about the default access, make that short and clearer and then revisit the sentence to adapt it.
"Choose which pages you want these access rules to apply to"