Just Wondering...

Why do patrons that come into the library to read, surf the Internet, and study always fail to read the signage in the library requesting things like 'No food or drinks allowed'; 'Please turn off your cell phones'; 'Please do not re-shelve books or magazines'; 'Do not leave children unattended'; or 'You must have a photo id to receive a guest pass'? They obviously can read but they seem blind to the written policies spelled out on the wall.