It's teaching the kids to be passive aggressive. Can't get what you want? Work behind the scenes to cause the people you love to do what you want. Do it to the kid, the kid does it back to you. It's not something to trifle with. You're configuring the personality of the kid with these interactions, and these choices have huge consequences about how the kid interacts with society, family and friends. There are only a couple people in the world I would trust with my life, whom I could give them power of attorney over me and I could rely on them not to loot me and leave me powerless. And that relationship is built on one of trust, one of never deceiving. The father is deceiving the kid, that trust-relationship I have may not materialize with the person who plays these mind games.
The relationship I describe is the most valuable thing on Earth, people KILL for it, literally, and I'm trying to comment here about how to get that thing, and I see these articles are pooping all over it, and I have to give my 2 cents. These ideas I have aren't silly, it's the operating principles of the most valuable thing in the world: Love and trust. The only thing worth more than money.
1. A zero tolerance policy on "lies" does have a psychological cost on both the parents and children (not just convenience) and, while it's great that has worked alright for you, that's not a proof that it can be generalized and get it working well for everyone.