PhoneView and Your Phone's Security
PhoneView uses the same methods of access used by iTunes, and it's subject to the same security constraints. If your iPhone is locked with a passcode, iTunes and PhoneView will not be able to access it on an unauthorized computer.
Your home computer has security keys stored which allow you to sync or use PhoneView without having to enter your passcode. If connected to a stranger's computer, entering the passcode would be required before any data can be accessed.