Pig Trader, on 2017-March-21, 11:14, said:
Playing Multi-Landy, over 2
♦ (alerted), most players would treat an undiscussed 3
♦ bid as natural and constructive (at least) e.g.
♠ x x
♥ -
♦ K Q J x x x x
♣ A x x x
Hence, prima facie, North's 4
♠ used the UI that South failed to alert North's 2
♦ overcall. Thus, the director should adjust the score, perhaps to a redoubled slam. Before the imposition of alert and equity law, that was a typical result of such misunderstandings
I suppose that North might claim that over a natural 3
♦. 4
♠ is a
fit jump but the director would need some convincing in an undiscussed auction. Especially as that logical alternative is suggested by the UI over other LAs (e.g. 4
♦, 5
♦).
(Anyway, as far as South is concerned, without tells from North, North's 4
♠ is likely to be an
auto-splinter, confirming a
♦ suit. Unfortunately, such tells are the rule rather than the exception after misunderstandings. Luckily, here, the director probably need not concern himself with such possibilities).
The director should also consider a procedural penalty, for a blatant and seemingly deliberate infraction.
WBF Regs - BCL but assume F2F regarding alerting.
1♣ = Alerted. May have as few as two clubs. (Strong NT, 5 card majors)
2♦ = Multi Landy, showing a weak jump overcall in either major but South had forgotten and thinks it's a WJO in diamonds, so not alerted.
3♦ = No agreement systemically. If North had called 2♥/♠ showing that major plus a minor, then 3♦ would be inviting game in partner's major. Not alerted.
EW want a ruling as they think they might reach 5♣, probably doubled and two down, for a better score than the 4♠= as happened
How would you rule?