ArtK78, on 2012-February-28, 08:42, said:
I would never bid 3NT with the East cards opposite a 12-14 1NT.
What I would do is sign off in 3♦ using whatever methods are available to the partnership.
Quite frankly, with the East hand, I would be more worried that the opps had a playable contract in a major than I would be about missing a game.
Missing this "game" turns out to be no catastrophe. Assuming that the defenders attack one of the black suits at every opportunity (certainly not a sure thing) 3NT will depend upon the ♦Q being onside (or 2-2 diamonds with the A onside if that is your line of play).
If I were playing the methods that I use over a 10-12 1NT then I would bid 3♦, which is defined as "slightly invitational."
Your method of signing off in a minor will tell you partner has <4 diamonds and <5 clubs, had partner shown 4 diamonds, would you be interested ?
The danger is not what partner actually has where tbh I don't care that much whether I'm in it or not, but that partner has Axxx, xx, AJxx QJx or similar where 3N is excellent, and 2N doesn't get you there, and lots of 14 counts where 3N is poor and possibly dialling a number if it doesn't make AKxx, xx, xxx, AKxx is not only going -1 a lot of a time on a heart lead if the diamonds are 3-1 without a stiff ace onside, AKxx, xxx, Qx, KQxx is also revolting on a heart lead and potentially dialling quite a few.
As you might gather from the above, my view is the 5th option, don't bid 2N but idc what you do.