[weejonnie]

In settling disputed claims the above words are often banded about. The following is obviously the start

"In ruling on a contested claim or concession, the Director adjudicates the
result of the board as equitably as possible to both sides, but any
doubtful point as to a claim shall be resolved against the claimer. The
Director proceeds as follows.

The part in emphasis is very wide - so the first question raised is "If an action is 'irrational' as opposed to 'careless' or 'inferior', does that mean that there is no doubt whatsoever that declarer/ defender will not take that line?

In most cases the word 'irrational' is not used and we are left with the helpful piece of advice

"* For the purposes of Laws 70 and 71, “normal” includes play that would be
careless or inferior for the class of player involved."

It is only Law 70E where the word 'irrational' appears

E. Unstated Line of Play

1. The Director shall not accept from claimer any unstated line of play the
success of which depends upon finding one opponent rather than the other
with a particular card, unless an opponent failed to follow to the suit of
that card before the claim was made, or would subsequently fail to follow
to that suit on any normal* line of play, or unless failure to adopt that
line of play would be irrational.

Second question: This sentence seems to deal initially with 2-way finesses and the such, however does the last part (underlined)actually apply to all unstated lines (not just the ones mentioned earlier in the paragraph?

So: the third question is: are TDs being encouraged to be far too eager to rule against claimants - and thus not rule equitably?

a) if there is any conceivable failing line should the claimant be forced to take it.
b) Any conceivable line not involving throwing winners on winners/ taking finesses through hands with voids, under-ruffing a trump in front of them, blocking suits should be considered. (A claim was disallowed in a major championship because it was felt that a world-class player could block the club suit)
c) Any play not involving a 'natural' 'pre-determined/ obvious' order should be disregarded (note this flies in the face of 70C, where the declarer is forced to concede a trump, If possible to lose due to normal play.

Where would you draw the line, in general?

[inquiry]

The troublesome issue is when a trump is left out and has not been mentioned.

The claimant, when ruffing, ruffs should ruff low and might get an overruff when ruffing high works. When playing trumps, the trumps are played from the top.

The question, do you (as the director) allow drawing the (unknown) trump? When it helps declarer, you do not allow it, when it hurts declarer (say master trump is the one out and playing a trump results in down more than just the master trump) you require him to do so. Try reading duplicate decisions on this issue, pay attention to the section on missing trump not mentioned in claim. Duplicate Decision Discussion of Law 70

[nige1]

In theory, the law on disputed claims seems clear and sensible, discouraging sloppy claims. Inconsistencies arise when some directors are generous to experts, judging that carelessness would be irrational for them, even when their claim-statement (or lack thereof) implies that they've lost the place. Imbued with so-called "Equity principles", such directors correctly judge that, in practice, the expert would wake up, if forced to play it out, especially after opponents dispute his misclaim.

IMO, BBO and Rubber-bridge claim-rules seem fairer and simpler.
.

[barmar]

My take on the "any doubtful point" clause is that it refers to borderline cases, where it's hard to decide if it would be careless or irrational. You're supposed to err against the claimer, so you should treat it as careless. But if you think an action would clearly be irrational, it's not a doubtful point.

Also, 70A is just describing a general principle, i.e. the spirit of the law about adjudicating contested claims. The remaining clauses go into detail about specific points, and they take precedence. So, for instance, when dealing with an outstanding trump, the standard is "at all likely" that claimer was unaware of it.