Years ago, playing 2/1 GF, Red on White, partner opened 1♣. My RHO overcalled 1♥, an apparent pick-off move, as I held AKQJxxx in hearts, and very strong general values. This created a problem. Fortunately, however, my strength was such as to justify good old Blackwood. 4NT.
LHO verified the ruse by raising the overcall to 5♥. Partner, playing D.0,P.1, rebid 5♠. Having all four Aces, and a trick source, I blasted 7NT.
This was quite interesting timing, as the MP event was in the last round, last board for us, on a late play. As we were doing well in the event, the crowd was gathered to watch this. When the 1♥ preempt had hit the table, the kibitzers were getting their standings worth. The 7NT call, the only 7NT bid on this hand for the evening, was quite remarkable, as it would easily be set eight tricks if my LHO simply elected a diamond lead, to his partner's AKQJxxxx in diamonds. Alas, a heart hit the table, and I scored up the grand.
Of course, one part of the story was the lack of a double by RHO for an unusual lead. Whether LHO would have worked out which suit to lead is another question, but RHO knew that passing was doomed.
The second part of the question is how reasonably competent people ended up in 7NT off the AKQJxxxx in diamonds. Is Blackwood too much?
Well, as it turns out, we had discussed a new treatment that my partner liked. With 5-5 in the black suits, he was of the school that opened 1♣ and then bid spades later, twice if necessary. Unfortunately, he forgot that the first spade rebid would technically be systemic, and I preempted him out of the second spade rebid.
I'm not sure what the point here is.