I disagree. I believe that there are many instances where a lie may be told without a sin ever being committed. If a person involved in a car crash asks in their dying breath if their wife/husband/child is safe; you answer: "Yes, certainly". Whether that is true or not.
If you were in wartime Warsaw and knew where a Jewish family was hiding from the Nazis, if asked would you say: "Yep, I know the basement they are in."
One of my favourite paintings is the one below, 'And when did you last see your Father?' by William Frederick Yeames. I find the picture strangely poignant and, of course, there are a number of situational rationales that one could weave from the characters depicted.
The scene depicted is from the English Civil War and shows a Royalist household with the son of the family being interrogated by the Parliamentarian official. In the background his sister, is being a bit girly and having a blub while Mama (?) and companion look on in grave apprehension. The boy is standing on what appears to be two tomes or, possibly, some form of low stool; a nice touch, it adds a slightly sinister air, making allowances for small children to testify.
And the question that we know has been uttered:
"Look at me boy - and when did you last see your Father?"
The answer is for us to imagine but, judging from the lad's stiff back and steady gaze, my guess is that he ain't going to tell the truth, no way. And he will not have committed a sin in so doing.