Is it dishonest to lie to the robber about where the jewelry is hidden? Or to tell the SS that you are hiding practitioners of the Judaic religion in your attic or basement?
Well, it’s an interesting question whether that is justifiably dishonest or not dishonest at all. But certainly they both entail being untruthful and this may lead to other untruthfulness. For example, is it dishonest to lie to somone you suspect to be a robber/SS or to anyone who might unwittingly help said robbber/SS? The tangled web of deceit.
Operating in an underground economy limits the economy of scale. This, too, has been discussed elsewhere on this forum.
If you are trying to state that appealing to an underground economy to escape government oppression (such as the black market in your other thread) establishes a case of ‘honor among thieves’, what you are missing is that it may be moral to do so. This does not make you a thief in principle, only a thief in the eyes of prescribed, immoral law.
It does, though, entail making distinctions about who you are honest with. In the extreme case (e.g. under totalitarianism) you become quite paranoid, not even trusting your own children. I had intentionally avoided giving a hard definition of “thief” exactly so that we might explore the various interpretations. But you describe it well here: thief in law vs. thief in principle. And this is, of course, exactly the sort of consquence that one would expect when law and principle conflict.
I’m trying to resist drawing a conclusion here in order to explore the various consequences.