When you tell a lie- you generally get caught out at some stage. If you lie to a journalist or during an interview, the consequences can be a lot worse. Not only is there the embarrassment of being caught out in an interview or a correction printed in a newspaper, if you are not trustworthy your reputation will be ruined with the media.
If a journalist is burned by someone who lied, it makes them look bad. Generally, reporters assume that if you tell them something in an interview that it’s factual. If you lie, they will never contact you again and you can be sure other media outlets won’t either.