Thank you to everyone for the replies - it's interesting that there doesn't seem to be any real sort of unanimity on what the ruling should be. I make it iviehoff, blackshoe and jnichols in favour of 1 trick each (billw55 as well, but he doesn't count since his starting point isn't the laws as written) and, on the balance of what they've said, ahydra, gwnn, Cyberyeti, Vampyr and Zelandakh in favour of both to the declarer.
billw55, on 2012-January-03, 13:19, said:
I have a firm opinion on this that I always post in threads like these: if declarer makes a claim that does not mention an outstanding trump, he should be deemed to be unaware of it.
In this case, if declarer thinks no trumps remain in defenders' hands, he might well play the ten, since he thinks it does not matter. I rule one trick to the defense.
Whether the laws actually support this is another matter. I am not a director and this is only a forum so I can say stuff like that

Thanks, but I was primarily concerned with the appropriate action within the laws, which fortunately do explicitly say what the TD should do if the the claimer does not mention an outstanding trump - my problem has only been with appropriate interpretation of "normal" within that section of the laws.
Vampyr, on 2012-January-03, 19:27, said:
Your wording was not "loose"; the meaning of "plain card" is, er, plain to native English speakers, and is used in bridge literature. Perhaps it is potentially confusing for non-natives, but it is difficult to predict that.
Kind of you, but I'll try nevertheless to be more careful in future postings not to use such terms. Mind you, the pre-edit OP did explictly mention
♦Q in the last paragraph, so I don't think it should have confused anyone who had read that far.
blackshoe, on 2012-January-03, 18:35, said:
The footnote quoted above was changed in the 2007 laws. In the 1997 version, it read "For the purposes of Laws 69, 70, and 71, 'normal' includes play that would be careless or inferior for the class of player involved, but not irrational." I honestly don't know why it was changed.
This raises all sorts of interesting secondary questions. Did this result from an intention to allow irrational plays possibly to be considered "normal"? And are people (such as you) who are aware that the change took place more ready to consider irrational plays as "normal" than those who are not aware that there was a change? Incidentally, whilst I attended an EBU TD course about the law changes at the time, I don't remember that majoring on alterations to the claim law footnote, but I don't have the course materials to hand right now and it may well be that it was covered and I've forgotten.
blackshoe, on 2012-January-04, 14:03, said:
There is nothing in the law about "self-evident".
"Inferior" isn't the only possibility. There is also "careless". And it would certainly be careless to play the ten.
BTW, the claimer isn't doing anything. Play ended when he claimed. It's now up to the TD to judge how the play might have gone, giving the benefit of the doubt to the claimer's opponents.
But also (as I said in the final paragraph of the OP) judging "as equitably as possible to both sides". It's interesting that you are the only person to have picked up on either of these parts of the OP's last paragraph.
I was about to post this when I saw VixTD's response arrive:
VixTD, on 2012-January-05, 08:45, said:
That may be true, but it still takes some thought and therefore a little care for some people to work this out, and therefore I think that ruffing with the ten could be considered careless. And to someone who thinks there are no trumps out, ruffing with the ten is a "no-lose" play.
... p93 of the EBU White Book has:
White Book said:
Suppose declarer claims three tricks with AK5 opposite 42, forgetting the jack has not gone. It would be normal to give him three tricks since it might be considered irrational to play the 5 first. However, with 754 opposite void it may be considered careless rather than irrational to lose a trick to a singleton six.
I think in such cases TDs tend to be divided into those who rule on the basis of what would likely have happened if the hand had been played out (declarer ruffs low), and those who (correctly in my view) consider what might conceivably have happened if the hand were played out (declarer ruffs low or high), resolving doubtful points against the claimer.
The White Book example cited is in the context of a declarer who states that he is cashing a suit, and the question being of whether he is assumed to do so from the top down. Whilst that's not really the context here, the underlying issue's essentially the same: what's "normal"? There are some other White Book sections that touch on the issue, but I note that, for example, 70.2 appears to depend on what's "irrational" and is possibly in need of review since the change to the laws footnote. More pertinent, perhaps, is 70.1, which says:
White Book said:
70.1 Interpretation of Law 70A
The TD is required to simply use his bridge judgement after consultation to decide the outcome of the deal, any doubt going against the claimer, with no opportunity for split or weighted scores. A suitable definition of 'doubtful' is 'within the margins of reasonable doubt'.
The implication of all this, it seems to me, is that White Book is accepting that at one end of a spectrum (eg playing AK5 opposite 42 when cashing out) there is really only one "normal" play, but much further along (754 opposite void) there is genuine doubt. Once one is in the "doubtful" area of the spectrum in any particular case, then I agree that one should rule against the claimer, but the problem remains as to where that starts.
There also remains the overall requirement to adjudicate "as equitably as possible to both sides". There is obviously some tension between these two provisions of Law 70A. Those who would rule one trick to the defence in all such circumstances are not, it seems to me, recognising that the "doubtful" provision qualifies the "equitable" provision without completely over-riding it, and that some such distinction is necessary for the two provisions to co-exist satisfactorily and for the tension to be resolved. The interpretation of White Book in this context that I've just given seems consistent with that.
Cyberyeti, on 2012-January-04, 11:51, said:
This seems completely illogical and absurd. The play of the 10 is not just inferior, it's completely no win, nohow never.
Zelandakh, on 2012-January-05, 05:28, said:
It is more than careless, it is also irrational.
I agree (and said so in the bullet points of the OP). But it's only irrational if the claimer actually can be assumed to think about her play (as jnichols remarks).
This arose in the last club game before Christmas; I wasn't expecting to direct, but did so because the scheduled TD didn't appear. Of course, by the time I got to the table everyone by then had their positions well prepared, which is one reason why I didn't want to explore here whether or declarer was aware of the missing trump - she certainly was when I arrived!
FWIW, after some thought I decided in accordance with those who thought that it would be irrational for her to have played the
♠10 on
♦Q and gave her both tricks. In doing so, I was conscious that the position was a very simple one - had it been a bit more complex, I might have made more allowance for declarer error. I should perhaps have made more effort to identify suitable people to have consulted on the ruling, but in the circumstances I didn't. E/W took the ruling with good grace.