I throw my racket a lot if I'm not within reach... as long as it's on your own court I don't see why it should be regarded as an issue.
it's successful in tennis at least twice. But tennis rule: The racquet has to be in the player's hand at the ball's contact point there're no rule like that in badminton so lin try it all the time but i think it should be illegal. Player can change racket during rally or rob teammate's one. So what matter is who hold the racket and the "linless racket" flying in the air hitting shuttle back to opponent court should be a fault