if i can tell my child is lying to me, i will be very upset towards him/her i would say .. "!!! if i can tell your lying, how do you expect the police or anyone else to fall for it???" i would then begin to try to teach those skills..
So you already consider that a good skill to raise your children with is the ability to lie to the police? Instead try teaching them right from wrong in the first place, that takes real effort and patience.
It's impossible to explain to someone who isn't a parent and I hope dm is right, my eldest is 7 and obviously I can tell when something is amiss, I can't always put my finger on how. My parents can do the same with me and I'm 35.
Judging by your sig you seem to be under the impression that being underhand and performing illegal activities is cool and you do it largely to impress others, you will no doubt deny this, if you do, even I will know you are lying and I can't even see your face.
As it says in your sig, you like to argue, can you simply drop the matter and admit defeat? That takes a bigger person. That is something your parents should have taught you to do.