This is why airlines (amongst other reasons) have interviews to discover a persons true personality.
All research into interview techniques has shown that face to face interviews will give the least accurate reflection on a person, they also tend to be biased, wat if the guy giving the interview is having a bad day, or doesnt like ur face!
that said, its still the most popular technique, but some people are realiseing its limitations, ie the police, at no stage are you interviewed by a person its all group work etc.