The bidding proceeded this way
1) When south bid 1NT, north alerted it as "forcing"
2) After west bid 2H, north looked at the table and said "oh sorry, I thought I opened"
3) North thought for about 4 seconds and bid 2D
4) East rejected the insufficient bid, and north corrected to 3D
3D just made for 110.
West argued that the UI suggested that south pass, since he knew his partner had 4 diamonds most likely, and asked that the result be adjusted to 3N-2 (spades were 5-1). West asserted 3N was actually clear in his bridge judgment.
South argued that this wasn't necessarily true, that in fact the UI that partner had an opening bid actually made bidding more attractive. He also felt that 3N was a poor bid, and if anything the alternative was 3H.
How do you rule?