Me: It is correct to teach kids that they should tell the truth in every scenario, even if as adults we don't.
You: Not correct. [...]
Exceptions exist in every situation for every single thing you say or do or think. Pointing out exceptions doesn't get you anywhere. Every adult knows this. A childs mind doesn't, and depending on the maturity level, cannot comprehend them. There is an established successful method of instruction of starting with simple rules/laws/examples, and then layering complexity later on. All of our systems of education are based on this. Nobody tells a child to also look up for a possible meteor or a skyscraper collapsing, or a vulture about to attack them before crossing the street. We just teach them to look both ways. Programmers are taught to take for granted that a bit in memory retains its value once set. When you're learning how to program you don't need to account for CPU bugs or cosmic radiation.
Me: It is correct to teach kids that they should tell the truth in every scenario, even if as adults we don't." teach children that truth is optional."
Optional means maybe. I said default is truth. And when I say every, I mean every. But there are exceptions, in the case of enemys. So if they lie to someone, it means this one is a (temporary) enemy. Which is a serious implication. They do understand that usually.
They also understand the concept of friend and enemy very early, I bet you agree. (not that they can allways correctly sort it out, but also we adults can't do that allways)
So they very intuitively understand the exception in the case of a meeting with a potential dangerous person and I bet, instinctivly act accordingly and not tell him, where others are hiding for example. (Or break down and cry, also a valid strategy)