(I don't think North has shown H+m opposite a partner who must pass once.)
> How do you rule?
North has UI that partner has an opening pass. I think this suggests bidding preemptively (randomly) over pass. I think Pass is a logical alternative for North: even opposite a partner who must pass once, there is the danger that partner might compete subsequently with inadequate hearts.
Having decided there is use of UI, it is less clear what to adjust to. If North passes, I suspect EW will still bid 6S and North will lead a heart. Even without being mislead about the position of HK, I can't see how 6S makes. So I would probably rule: table results stands, and a procedural penalty to North for use of UI (assuming the TD explained the UI position when called for the opening pass out of turn). An alternative ruling is AVE+/AVE- under Law 12C1d because the outcome after removing the initial 2H is too difficult to determine.
South could not know when he passed out of turn that North might bid hearts and mislead EW as to the location of HK, so there is no law seventy-something adjustment.
(I don't really like ruling UI here - I think the law, having silenced South for one round, should leave North free to act.)
> It is alleged that N/S gloated for the next few rounds about the clever trick
> they had pulled: as TD, what would you do?
(They gloated for several rounds? Even with different opponents at the table.)
A disciplinary penalty for each batch of gloating. 1VP, then 2VP, then dismissal.
> After the TD had taken certain action the N/S team walked out,
> as did another team local to themselves: what action would you take?
(Isn't "local to themselves" tautology? ... another team local to original N/S team?)
Knowing me, that action I would take would be to end up with two triangles.
I have no interest in a contestant once they have walked out, except to recover the movement for the remaining contestants. I apply standing regulations to the scores of the other contestants against the withdrawn contestants.
I write to the tournament organisers and/or the national body, reporting the fact that the teams walked-out and recording the circumstances of the ruling and misbehaviour.