Ok, here's the full deal. I got some of the spots wrong when I reproduced the hand from memory (the ACBL web-site was down), but the critical spots in the heart suit, 965 in North's hand are correct.
South believed that playing the Nine first and following it up with the 5 later (playing UDCA) was suit preference for clubs. He played a club and watched in horror as declarer grabbed the trick with the King and played a club. South was on lead again and shifted to a spade now. Declarer plays a low Diamond to dummy's 9 and pd's T, takes the next spade, ace of Diamonds felling the Kinganf finally ruffs his good spade with a Diamond and gets out for down 1.
We analyzed it later to see if it makes any difference if South plays Ace and Queen of clubs, now pd wins the third club with the Jack and can play a low spade. If declarer plays the Ten he's home again for down, but if he plays a higher honor, then a Diamond to the nine, North can with with then and play back a Diamond. Now if declarer plays the Ace and another Diamond, North can exit in Diamonds, the defense scores 1h, 2c, 2d and 2s for that magic +200.
If South plays a spade either because North followed with the six of hearts at T2 or independently (?) comes to the conclusion that a spade is likely to cause less damage when it's wrong than a club switch, North takes the Ace and exits a spade, passive defense eventually end-plays South into playing clubs himself from his own hand for -200.
The king of Diamond shift wasn't given much thought by South at the table and I thought later that it didn't appeal to me. But looking at it now, it seems okay. Problem is that declarer is likely to duck it, in which you must continue the suit and eventually defense will prevail.
This is the kind of bread-n-butter MP deal where it appears as though the 1D opener doubled mainly to take NS out of their comfortable spot of 1nt knowing it'd be hard to defend it solo. If NS recognize it as such, i.e, that it's a low-level part-score with no great fit for either side, shouldn't them be doubling to protect their plus score just in case they chuck a trick on defense ? Note that with his 14 and partner's 1nt response vul, South should have enough confidence that they have the balance of strength. Even if opener has five Diamonds and say two clubs instead of 4-3, NS can still beat the contract 1 trick easily.
Imagine how much harder NS have it if EW weren't vulnerable. Now not only would they have to double, but have to beat it two tricks, as they're almost sure to make +120. There were quite a +150 for NS.
BTW, Phil, you won't get it out of me if I was sitting North or South
Seeking input from anyone who doesn't frequently "wtp", "Lol" or post to merely "Agree with ..."