You can
unlock somebody’s phone without having their passwords or locking code. When
someone succeed to get access to someone’s phone they can see the call history,
voicemail and even make calls.
Secondly, there is a software program that allows people to get in your Facebook/email/Twitter etc, when you are using a public WIFI signal. They can read your (private) messages and even send messages or change some settings. Doug Stewart is giving some tips to avoid this in the video.