The Final of the 1991 World Teams Championship (contesting the Bermuda Bowl) in Yokohama, Japan. Iceland plays Poland and you are seated behind Icelander Arnarson, South. He has:

¹ Polish Club, three possible types of hands:
  a. either 12-14 balanced
  b. or 15-17 unbalanced, 5⁺ clubs
  c. or 18⁺ any distribution (but not 18-20 balanced: with that hand he would rebid 1NT)
² Ruling out possibility b, leaving a or c (but if c, then limited, 18-20, and, since West doesn't bid 1NT, unbalanced)

South was too weak to bid 1♥ voluntarily over 1♦. The subsequent bidding stays at a low level, however, and over 1♠ South has to decide once more: bid or pass?
He doesn't know and hands you his cards. What is your decision?

Although South is very weak, he may assume that EW are not very strong either. Why else would they settle for 1♠ only? Their bidding system is rather complicated, but if they decide to stop short in 1♠, they will know what they are doing, won't they?
Furthermore the chance of partner having four hearts is substantial, since EW opt for a spade contract. Combined they will have at least seven spades therefore, so partner has three spades at most. Usually a player who doubles a minor suit for take out, shows at least seven cards in the majors. (We have to put this in perspective at once: in view of EW's modest bidding, North probably has extra strength. This means his distribution does not necessarily meet the demands of a minimum take-out double. 'When doubling for take-out: the stronger the hand you double with, the less it needs to meet the distributional demands for a take-out double').
Although at IMP-scoring the 'big numbers' count — meaning we usually avoid risks — a 2♥ bid on this hand looks right: partner is expected to have extra strength and if not he will certainly have four hearts.
Bidding 2♥ is exactly what Arnarson did.
But then Martens, West, doubled and South played there. So you bid 2♥ and immediately you are being doubled... Wrong decision therefore?

S/—		♠	K 8 6
		♥	K J 8 7
		♦	A Q 10 5
		♣	5 2
♠	A 10 4 2			♠	Q J 7
♥	A 6			♥	5 3
♦	J 2			♦	K 9 8 6 3
♣	A K Q 8 7			♣	J 10 3
		♠	9 5 3
		♥	Q 10 9 4 2
		♦	7 4
		♣	9 6 4

West, who earlier couldn't rebid 2♣ instead of 1♠, since that would have shown either possibility b or an 18-20 hand with six clubs, doubled to show the stronger (18-20) of two varieties. The double showed nothing in peculiar in hearts: he could have little in that suit (for instance a 5-2-3-3 distribution) but four hearts and a 5-4 hand in the majors was possible as well. Therefore East probably should have pulled the double, retreating to 2♠ (he didn't know about West's five-card club suit, of course).

So it looked from the bidding that East was playing all-or-nothing. And so they did both Poles in defence. West led the ♣A and switched to the ♦J, which went to the ♦Q and the ♦K. Now the return of a spade (or a club, followed by a spade switch) would have led to down one, but East wanted it all and hoped for a singleton diamond with his partner. So he played back a diamond.
Declarer won with the ♦10 and played trumps. Later he pitched a spade loser on the ♦A and happily recorded +470 for 2♥ doubled made.

Back to the bidding: now that West turned out to be unexpectedly (to East, obviously!) strong, North did not have any extra strength — which is what South more or less expected. However, as a consequence of North having a minimum double, he was certain to have a four-card heart suit. And so he had.

At the other table Iceland (EW) went down two in 3NT for −100. The 370 points difference gave Iceland a 9 IMP profit.

Moral: if a player passes once since he is weak, that doesn't mean he keeps on passing. Good players tend to re-evaluate their hand in every new bidding round.
Something else: he who doubles a part score contract, had better defeat it!