In my opinion there are no rules for the DM, just guidelines. If there's an agreement that the DM plays by the same rules, then I can see how someone might also think making misleading rolls would qualify.
In any case, it totally depends on what has been agreed to. I just think the default is that due to Rule 0 the DM can do whatever he wants.
To a certain extent, that's probably true in most groups. I know that it's not true for other groups, and that deviating from what you agreed explicitly to do (or not do) will upset many groups or players. So, yes, it depends on what you agree to.
Fudging is the same thing; that is, it depends on what your group agrees to. Your default is not mine, though the GM will get away with a lot. That means if I do fudge, my players will be upset, because we have agreed that doing so is less fun.
If I was to play in your group, I'd go by your rules without really questioning them. If the play experience became less fun for me because of suspected fudging or abuse, I'd bow out. However, if it was subtle enough that I didn't catch it, or it was never abused (as is likely the case), I probably wouldn't care (because I wouldn't know about it).
If I was told at any time, though, that fudging was practiced, I'd probably have to never suspect it again, or bow out. I just feel like I need to earn it, and fudging lessens that feeling for me, and it draws my attention to the dice, and out of immersion.
But that'd be my problem, not yours or your groups' problem. You're not cheating, from the sounds of it. Thanks for the discussion. As always, play what you like
