[Gazumper]

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On the lead it looks like clubs have to split or the diamond finesse has to be on but GIB makes it easy by not covering the ♠9 which would otherwise cost nothing.

Edit:
I've been playing about with this hand in the editor and it seems as long as the hearts behave the contract is 100% because of the myriad of squeeze possibilities. I can only assume GIB saw everything and calculated from the bidding that it wouldn't make any difference to duck whereas any human would surely cover to give declarer the opportunity to make a mistake.

[AyunuS]

It sees this as 100% win for you. You bid 24+ points, so west has at most 2 points. Therefore, you have every A, K, and Q, except the Q of spades, but it led spades so it doesn't have that, either. 4 AKQs is already 12 tricks. Then it also knows you have at least 2 of each suit, so with the 2+ hearts and at best for it a 3/3 heart split, it figures you also have 5 winners in hearts, so you just simply win for having more than 13 top tricks. It doesn't care what to play on defense when it sees it as 0 chance of winning any tricks regardless.

[Gazumper]

GIB can be exploited in that way. Any human would play the ♠T since it costs nothing and hope for a mistake, South cannot claim 13 tricks until it plays a few cards.

One way I've had fun with GIB is to open 2♣ with a Yarborough and pass whatever partner bids, it can throw GIB right off and get a top score. It can also go bad of course.

[slar]

Gazumper, on 2017-February-01, 01:21, said:

One way I've had fun with GIB is to open 2♣ with a Yarborough and pass whatever partner bids, it can throw GIB right off and get a top score. It can also go bad of course.

And that is why psyching a conventional bid is forbidden in most organized play.