Actually tygxc, the position you put on the board is not possible. The only way for the white bishop to be on a1 is if were already on the long diagonal, which it could not be as the black king was already on h8. If you had placed it on say, d4 then that would have been possible. Of course, then black's last move would have been to trap himself in the corner with his own bishop. Possible, but not likely. I think the misunderstanding here is the missing word "forced" before the word mate. There is no forced mate with opposite colored bishops. As for the question of trying to win on time, I see no ethical problem with that. I'm old and slow, and somebody that can move quickly can beat me easily in fast games. However in say a otb tournament game with 40 in 2hrs time control, I can put my opponent into complex positions that they may have to burn time trying to figure out the best moves. If I were to win a game that way, I would certainly feel no guilt.
Ethics question
It's possible if White's King moves to reveal the checkmate. It does require some inadvertent cooperation from Black which is why it's considered a case of insufficient material.
@28
@29
"6.9 Except where one of Articles 5.1.1, 5.1.2, 5.2.1, 5.2.2, 5.2.3 applies, if a player does not complete the prescribed number of moves in the allotted time, the game is lost by that player. However, the game is drawn if the position is such that the opponent cannot checkmate the player’s king by any possible series of legal moves."
https://handbook.fide.com/chapter/E012018
In an over the board game, an arbiter would probably ask the players nicely to stop the nonsense and stop wasting everybody's time (if they play with bishop vs bishop and nothing else.) Even if there is an additional h-pawn, as in the game in question, the position is so hopelessly drawn that it is absurd to play on.
As for the situation when the player with less material tries to flag the other player with plenty of time on the clock, that is just plainly absurd.
@32
The arbiter must not intervene.
"12.6
The arbiter must not intervene in a game except in cases described by the Laws of Chess. He shall not indicate the number of moves completed, except in applying Article 8.5 when at least one flag has fallen. The arbiter shall refrain from informing a player that his opponent has completed a move or that the player has not pressed his clock."
https://handbook.fide.com/chapter/E012018
Absurd is to play without increment in the 21st century.
All FIDE competitions are with increment now.
Play without increment leads to flagging in say KR vs. KR.
Playing with increment changes nothing. If one player wants to play on a hopelessly drawn position, why would increment stop him doing so?
In fact, there is empirical evidence that it does not stop them. In Titled Tuesday (which is played with increment), there is always a game in every second round where players aimlessly shift their rooks around in rook vs rook (no pawns).
It doesn't matter if mate is possible. All that matters is whether you have "mating material". A lone bishop is not considered "mating material".