Declarer ducked the ♣K from East and won the ♣continuation by East , ran the ♠9 to East's ♠A , won the ♣continuation , ran the ♠suit. East was strip squeezed and was reduced to ♥A♦KJ ♣109 and so declarer was home with the last 3 ♦tricks. for a score of +650 to NS.
NS managed the bidding & play smartly. Could EW have done something to reach their par of 4♣X ? by way of better partnership agreement, reasoning or judgement.
One way is to play the 3N X by E is to ask partner to decide to defend or bid since East can pass 3NT when he knows defending is best for their side.
Could the auction & actions be different for other vulnerabilities ?