[Mbodell]

xcurt, on Apr 11 2010, 06:19 PM, said:

2. It's probably theoretically wrong to pass out 4H on the South cards, but I'm pretty sure that enough peers would pass that it's a LA. I feel pretty strongly that you can't claim some action isn't an LA because you can construct a non-obvious, but strong argument that the non-LA action is nullo vs the action you wanted to take. Allowing such reasoning let's OS exploit the UI to avoid errors, even outright blunders.

It depend how "non-obvious" the argument is. Because what you are really doing is figuring out who the peers are. I'd like to think my peers are composed from people who would find a double with the south hand as a WTP action. Maybe I'm wrong, and maybe a poll of players with roughly my ability/experience level and roughly my familiarity of playing this nt range would find some people passing.

I'm sure a bunch of beginners would pass this (I'm not saying only beginners would pass this, just that sampling beginners would get some votes for pass), but that is because many beginners don't double without the complete setting tricks in top trumps in their hands. That shouldn't effect what is a LA for me.

[jallerton]

I would have doubled if partner had passed over 4♥ in tempo, but the problem is far more difficult when partner takes a minute to pass, as the slow pass demonstrably suggests that I bid on.

I would have to wonder how obvious double is: the hand has good defence, but you had been planning to pass out 2S.

I did a simulation of South’s problem and was surprised quite how much double does gain: if LHO bids 4H on most hands with a decent 7-card suit, double gains about 3.4 imp/board on average over the 20 hands I looked at. [Maybe this just proves that it is wrong for 4th hand to jump to 4H here without considerable playing strength. East may have thought that this was obvious, hence the reason why he could not envisage 5H going more than one off]

However, my simulation does not help South in the present situation. Players do not have access to simulations at the table. Nor, crucially, are they able to poll their peers to determine whether a non-suggested action is a logical alternative.
It is ironic that a South who tries to do the ethical thing by changing his intended double to pass loses unnecessary imps when it transpires that he could have "got away" with doubling.