Flag Fell - Should Time be Reinstated?

Checkmate ends the game instantly. It does not matter what happens with the clock. B loses.

Agreed - of course - and this all reflects the fact that clocks were a practical contrivance added to the play of the game long after the game existed - and their importance remains as such.

Even if we changed the example and mate was not on the board, since both players agreed to the result the result stands.

I’ve seen situations where players shook hands but afterwards it turned out they weren’t in agreement as to what the result of the game was!

And I know of one case where a player said checkmate and the opponent reflexively shook a hand with one hand while capturing the checking piece with the other.

What was the ruling on that game?

The floor chief (NTD) ruled that the game continue. On appeal the chief (ANTD) ruled that the game continue (the word checkmate was invalid, there was nothing valid said to determine what the handshake meant, the two players were obviously not in agreement about the handshake). On further appeal the appeals committee (no special arbiters existed yet) was split with the SrTD voting that the game continue and the LTD and CTD voting that the player saying checkmate won because the handshake was a resignation by the opponent, so the 2-1 vote finished the game and the CTD/LTD overruled the NTD/ANTD/SrTD. It was later appealed to the USCF and I never heard the outcome of that.

The rules committee did use that appeal, among others, to state that TDs involved in an appeals committee should be accredited at least as highly as the TDs being appealed. If that wasn’t possible then a special arbiter should be called.

Perhaps the player who “reflexively” shook his opponent’s hand “heard” the equivalent of, “I resign.” Usually, when a so called mate ends in the capture of the checking piece, the ersatz mating move was a horrible blunder. Of course, this check could have been the start of a grand combination but without seeing the actual position, who knows? I would have also trusted the floor NTD to have made the correct call.

My ruling: I ruled that, under the same logic as Eastside, Player B could not have run out of time unless Player A double tapped. I also know Player A has a history of double tapping. Additionally, I know that Player B almost always moves quickly/instantly in time pressure and is very good about punching his clock. If Player A did not have a history of double tapping my decision would have been much more difficult and I would have probably granted Player A’s time claim, having no other evidence or history to go by.