> In that case, it's illegal to look in the phone book for names starting with "john" because that's not a specific user.
Only if everyone in the phone book has a privacy interest requiring a warrant to breach in the fact that their name was in the phone book. They don't.
But imagine for a second they did. Then your search for "John" in the phone book would have involved flipping through the phone books pages looking for the "John" section, in the process violating the privacy rights of everyones names you looked at to figure out if you where before or after the Johns section. Of course that would be unconstitutional. It would be like trying to figure out where John lived by searching every apartment until you found the apartment with John's diary in it.
Only if everyone in the phone book has a privacy interest requiring a warrant to breach in the fact that their name was in the phone book. They don't.
But imagine for a second they did. Then your search for "John" in the phone book would have involved flipping through the phone books pages looking for the "John" section, in the process violating the privacy rights of everyones names you looked at to figure out if you where before or after the Johns section. Of course that would be unconstitutional. It would be like trying to figure out where John lived by searching every apartment until you found the apartment with John's diary in it.