Yesterday, I showed this hand where Geon didn’t bid 7♥. The screenshot is from BBO.
Within 10 minutes, I had 2 mails in my inbox, one from north and one from south, saying that the auction was wrong. The operator had missed a few calls, in reality it was this.
Natural opening bid and GF response, 2NT showed heart support, 3♣ and 3♥ asked, 3♦ followed by 3♠ showed 17-19 with 3♥, 3NT was a slam-try, 4♣ cuebid, 4♠ and 5♠ asking for aces and kings, with north showing 2 keycards and both minor suit kings without the ♠K.
At this point south signed off in 6♥, as he couldn’t count 13 tricks yet, wasn’t 100% sure about all the bids and doubted that the other side would bid 7♥ anyway.
While it is correct you that you cannot count 13 tricks yet, the odds are heavily in favor of bidding 7. Partner has shown 13 points but promised 17, thus he may have a minor suit queen. If that fails, the spades can split. 4-3. A quick simulation shows that partner will have a minor suit queen in some 70% of the cases, and the spades will split 4-3 in 63%. Either of those options comes up in 89%. Those are pretty good odds and they actually increase a bit to about 94% because partner may have a minor suit jack and the finesse is on (44%) of the cases, or somebody may have ♠Kx with partner having the ♠Q. In fact, the actual north hand is about the worst partner can have.
In short, it is a great grand and should be bid.