Several years ago we had the auction p - p - 1H - p - 2C - p - 2D - p - 3N.
2C alerted as 3-card Drury
2D alerted as asking for shortness.
3N alerted as "This bid doesn't exist in our system."
I later told partner that he doesn't need to alert when ...
A national director had told me some years ago that any bid over 3NT starting with responder's second bid is not alertable. Thus, the auction 1H - 1S - 4C would still be alertable if a splinter.
Perhaps I am mis-remembering, perhaps I was misinformed, or perhaps the laws have changed ...
At the table I looked at all my major suit losers and thought 3♦ might earn us -200. In reality, partner had a max and both 2♠ and 3♦ make, so passing led to a bad result. Partner held Ax xx KJ10xxx Q10x.