Apologies for duplicate and wrong hand. Using my phone and problem with async interfaces too (sometimes it seems everything is designed to undermine and make you look bad)
I was lucky enough to end in 5H via Soloway
Half a dozen others fell foul of this 4NT (no Blackwood) usage. Last hand of a Bot tourney
Is that common usage of 4NT after trumps appear to have been agreed, but I appreciate its a 1 over 1 situation etc
And they were all Americans playing in an ACBL tourney. I'm playing an alien system. I do ok sometimes