I don't think lies need always be a selfish act that should be likened to robbery of the truth. It's wholly possible for us to lie having the concerned person's best interests in mind. Some may view that as misguided or myopic, it need not always be the case. Indeed, telling the truth for its own sake without much thought or consideration to its consequences may be considered equally ill-considered and short-sighted.
Can Practical Wisdom be a reliable indicator of when to lie? So long as such people and purposes tend towards selflessness. The whole point of Practical Wisdom is using your experience and good intentions to act for the sake of others concerned, when dealing with scenario pre-existing rule's weren't meant to consider. Practical Wisdom thus describes when a white lie is necessary.
Should we rely on those who don't always tell us the truth?
In short, yes. And not only because we have to. So long we trust lie to us only as a last resort or given no other choice, and so long as they have our best interests in mind and have consistently demonstrated as such in the past, then those we rely on shouldn't always have to tell us the truth.
Are purposeful omissions lies?
If an omission completely distorts the nature of the information provided, then of course it is a lie. On other occasions when the impact of the rest of the provided information is minimal.
