A player has every right to do this. It is his time and not anyone else. No player should be discriminated for letting his clock fall for trying to find a move "in hopeless position" looking for something in position. If player not like this they should play faster chess. This is why 1 minute and 3 minute are most popular online chess time controls. I find it almost a discrimination to criticize player for "letting his clock fall" by the last lichess warning I got when I actually made a move but server not that great so it never even registered!!! The warning should be removed and unsportsmanlike to tell player how to use his time in 3 minute chess. I have every right to have think in 3 minute game. Save those warning for slow games not blitz THANK YOU VERY MUCH!!!