1) If law enforcement ever has the time, they might want to play Maffia or Werewolf. Playing those games enough makes you realize how idiosyncratic lying can be.
2) I'm glad to know that my lecture on lying when I studied psychology basically had the same conclusions as this article.
In my view this is just one more error springing from the root error of turning "a jury of your peers" into "a jury of random strangers". One point of being judged by a jury of your peers is that they are familiar with the types of things you're likely to do.
But another is that your peers are familiar with the ways in which you're likely to react to things.
How can you trust your judgement on whether they’re truthful about bigger things?
You can't. You will believe what you want to believe, and good liars are great at finding out what you want. A well constructed lie rests on verifiable foundations - ie. they also know when not to lie to earn your trust - and comprises of almost exclusively truths. There is no way to defend yourself once you become the target and start listening.
The only winning move is not to play.
(Even if like me you won't end up playing the game I found the experience worth five dollars)