Haha, too true. But a lie can't be a tease?
In an effort to "show you all" I googled the definition
http://en.m.wikipedia.org/wiki/Lie
Mea culpa
Intention to deceive IS important.
So I guess the hypothetical little bugger (I don't actually have any kids) did lie. Reading further it looks like this sort of deception falls under the category of "lie by ommision". On the other hand what I do to my wife is a "jocose lie".
That was one of the more informative/interesting wiki stumbles.
What the hell was wrong with St Augustine though?! A lie that harms no-one and saves someone is "more severe" than a lie that harms no-one and /helps/ someone?! I must be misunderstanding his classification scheme