The purpose of this post is to establish the meaning of 'liar' in science and elsewhere - it is only coincidentally related to tactical honesty.
From Wiki 'Straw Man' http://en.wikipedia.org/wiki/Straw_man
"The origins of the term [man of straw] are unclear; one common (folk) etymology given is that it originated with men who stood outside of courthouses with a straw in their shoe in order to indicate their willingness to be a false witness [for payment]."
[Knowingly bearing false witness] = [Liar] and any laws or customs relating to perjury should apply.
There are (must be) witnesses who are simply mistaken, deluded, ignorant and/or otherwise bad witnesses - for present purposes assume they honestly believe what they say to be 'true'.
A fair court can't reasonably expect witnesses to do anything more than say what they believe to be true (consider the alternative).
[Sincere and wrong] != [Liar]
[Insincere and wrong] = [Timewaster]
[Insincere and wrong] = [Liar] ?