I know, and those of us with siblings can probably remember occasions when we did the same as children. But I don't think that this changes the basic thrust of my argument that when such practices become widespread, it is dysfunctional. Even among chimps, deception of one's mates is limited to specific circumstances like this, and done occasionally, not as a matter of course. When it becomes the norm, and deception is constant and present in most or all aspects of daily interaction, then society breaks down, and the group suffers, along with all the individuals in it.
x42 did that a lot.
Cordially,