[FrancesHinden]

We're all agreed that signing off over 4D was a very poor choice, North has a slam drive now.
But I don't mind the 2S bid on the first round so much. If you are in the 'double shows an opening hand with shortage in the opponent's suit and 4-4 in the majors' camp, then, yes, it's a game force.
However, many people now would double 1D on, say, AQx Qxxx xxx KQx. If you are a 'get in the auction at all costs' doubler, then 2S is plenty.

[the hog]

I really dislike the x by St, but as stated above, that is irrelevant. Nth underbid the hand badly the first time and ridiculously the second time. Nth 100%

[Trinidad]

The problem is caused by North's choice of system. If South needs to double on every opening hand that is not a 1NT overcall, then North doesn't know that there is a spade fit. If South has a minimum opening with 5 hearts (e.g. ♠A♥Axxxx♦KJx♣Jxxx, where everybody else would overcall 1♥), South needs to double. Opposite such a hand 2♠ is indeed plenty enough.

The next problem arrives in the next round. North will think: "What the *&%$^$@ is 4♦?". He interprets it as a GF hand without direction -not as a slam try in spades, because the fit was not known- and he shows the fifth spade by bidding 4♠, hoping that there is a 5-3 fit.

So, the cause of the problem is that North plays an LOL system and South plays a system for players who understand bidding. You don't get good results by playing two different systems. If South would have been a genuine pro (the kind of player that gets paid to play well with LOLs) he would have played North's system. That means he would not have bid 4♦, he would have bid 5♠. There is no guarantee that North would have bid the slam (scary without asking for aces), but that would have been the best shot.

So, North is 100% to blame for refusing to learn what a take-out double and an overcall show. South could have done better if he would have fully understood the implications of North's horrible system. But I think it is cruel to first ask South to play such a system and then blame him when this system causes a bad result.

I hope South got paid very well.

Rik