Well, I don't have any proof one way or another but my common sense says that when people are saying two things that mean the opposite of each other, one or the other has to be untrue, if not both. Of course, there are "honest mistakes", and "differences of personal interpretation", and "misinformation" if you don't like the technical term lies.
For example, if person A says he/she believes that person B is the greatest thing since sliced bread and would never do anything to hurt a child and wouldn't lie either, so there! And person A also says that they believe that person B is lying and had something to do with it. Can both be true at the same time? Or if person A says there was a fight, and person B says there wasn't a fight. Or if person A says person B passed her LDTs when in fact B didn't, did person A tell a lie or did someone else tell him/her one?
Another example: Did Ron lie on TV when he stated on NG the other night that he wasn't concerned that Misty had flunked her polygraphs, and that he supports her completely until he gets delivered some proof that she lies about anything? IMO he had better be lying about not being concerned because it's just unnatural for any parent not be concerned about information with potential serious consequences regarding the fate of their child. The only reasons that I can think of that would make the first part about unconcern about the epic fail is if he set her up to fail and achieved the desired result, either because he wants to sleuth her out and get her arrested finally or frame her as a scapegoat. But in that case the other part about supporting her totally was a lie...
There just are times when you can't have it both ways and you must either eat the cake or lie about it.