[StevenG]

 lamford, on 2016-September-26, 17:02, said:

And in this example, someone can and should be able to conclude that a BIT means the player has the ace

I'm actually rather curious about this assertion that nobody has challenged. My experience is that players of a certain class or better always play in tempo when they have got the ace, because they have anticipated the problem. A fumble suggests they haven't got the ace and hadn't anticipated the switch to the suit. I certainly improved the accuracy of my guesses at the table in tournament play working on this hypothesis. For players below this class, a fumble usually means nothing at all.

[manudude03]

At the point the spade is pulled out, the options are either to put the card back and replace it with a club, or knowingly revoke. The latter option violates 72B1 which is a much stricter law than 73C1, and is in itself a demonstrable bridge reason. Yes, the defender shouldn't have pulled the spade out in the first place, but the reason is understandable, and as I said way back in my initial reply, I would simply warn the offender about doing that.

Also, if you consider law 73C1 in context of the rest of the law book, it is implied that Law 23 doesn't automatically come into effect (if it did and Law 23 was a catchall, then it wouldn't be mentioned on many other occasions throughout the book).

[nige1]

Suppose: declarer leads towards dummy's KJx, LHO (holding the queen) pulls out one card then plays another, declarer plays dummy's king, and RHO wins with the ace.
IMO:

If LHO says he has a reason for his performance, conceivably the director might rule in his favour
e.g. LHO might have a known medical problem.

At the other extreme, the director should rarely accept an irregularity by LHO as justification
e.g. "I anticipated what declarer would do next, so I pulled a card out ready to play" doesn't cut the mustard,

Normally, the director should rule in favour of declarer, on the grounds that LHO could have known that his behaviour might imply that he held the ace.

In the general case, this would foster consistent rulings untainted by suspicion of caprice or cronyism.

[pran]

 nige1, on 2016-September-28, 06:54, said:

Suppose: declarer leads towards dummy's KJx, LHO (holding the queen) pulls out one card, then and plays another, declarer plays dummy's king, and RHO wins with the ace.
IMO:

If LHO says he has a reason for his performance, conceivably the director might rule in his favour
e.g. LHO might have a known medical problem.

At the other extreme, the director should rarely accept an irregularity by LHO as justification
e.g. "I anticipated what declarer would do next, so I pulled a card out ready to play" doesn't cut the mustard,

Normally, the director should rule in favour of declarer, on the grounds that LHO could have known that his behaviour might imply that he held the ace.

In the general case, this would foster consistent rulings untainted by suspicion of caprice or cronyism.

Your example is completely irrelevant for this thread.

Remember that (according to OP) declarer played three rounds of trumps without any hesitation and then suddenly switched to a different suit instead of pulling the last outstanding trump. Declarer knew that this trump was held by LHO, and LHO knew that Declarer knew this.

So this is in no way comparable to hesitating or apparently changing ones mind with a Queen to the left of KJx

[lamford]

 StevenG, on 2016-September-27, 08:53, said:

I'm actually rather curious about this assertion that nobody has challenged. My experience is that players of a certain class or better always play in tempo when they have got the ace, because they have anticipated the problem. A fumble suggests they haven't got the ace and hadn't anticipated the switch to the suit. I certainly improved the accuracy of my guesses at the table in tournament play working on this hypothesis. For players below this class, a fumble usually means nothing at all.

Then you must play against some very unusual people who fumble without the ace but play smoothly with it. In my experience, even good players sometimes break tempo with the ace but never break tempo without it as they know they will be adjusted against. And in answer to pran, it does not matter in the slightest why the person broke tempo.

And you would improve your guesses even more if you play the king after a fumble and call the TD if it loses.