Yes. You must complete your move and stop your clock with the flag still up. When you release the piece on the square, the move is “determined” but not “completed.” This is explicitly covered in 9F: “The player’s flag may be up after releasing the piece, it may be up while hitting the clock, but if the flag is down after the move and the opponent has not yet handled the clock, the player has failed to make the time control.”
I’m not sure what your second paragraph means, or has to do with anything, but the player has to be able to prove that he made his fortieth move with his flag still up. Even if hitting the clock causes the flag to fall, it counts as a flag fall, and the player loses, assuming the opponent has a complete enough scoresheet.
The opponent can claim a win on time. The only exceptions would be if the determined 40th move immediately ended the game (checkmate or stalemate) or if the opponent had too little material to win prior to the 40th move being played.
Certainly. There are a number of such reasons. If the player’s flag falls before he completes the last move of the time control, his opponent may attempt to claim a win on time. If he meets all the requirements (including a reasonably legible scoresheet complete to within three move pairs), the TD will rule in his favor. But all of this is rather far afield from the original question, which was whether a player whose flag falls before he has completed the last move of the time control has made time control. He hasn’t. Whether he actually loses on time depends on the circumstances.
The most common example in USCF tournaments is when the opponent is blitzing the player whose flag falls, without bothering to record the moves.
Then often the player will not know any better, and just concede that “he lost on time.”
Or occasionally a player might actually know the rules, and the game would continue, accompanied by the opponent complaining and ranting something clever, like “Well if he doesn’t lose on time when his flag falls, then why do we bother to use clocks at all?!”
I’m not going to argue about whether the TD should do as Grant suggests. (I think it’s obvious, but apparently you do not agree.) I will point out only that the TD unquestionably has the right to do so under 11J. (If, in the TD’s judgment, the illegal move was deliberate, he may impose penalties at his discretion.)
Let’s consider two cases. Last move of the time control, non-sudden death.
a) White makes the last move of the time control. His move is illegal. Black’s flag falls before he can make a move. Unless Black actually says he resigns before I can intervene, I’d rule that White’s illegal move a) must be corrected, and b) distracted or annoyed his opponent. Penalty: White’s claim of a win on time is rejected.
b) White makes the last move of the time control. The move is legal. Black makes the last move of the time control with his flag still up, but his move is illegal. There’s no question of claiming a win on time (since both flags are still up), but if White complains, or I see it, Black must make a legal move instead, and if Black’s flag falls before he makes a legal move, he can still lose on time. (11A and 11H, “The time on the clocks shall not be adjusted.”)
Do you disagree with one of these, or do you have some other scenario in mind?