This is the first part of a 歇後語 that originally had 唔聽佢支死人笛 as the second part. The story goes that when a deaf man attends a funeral procession as one of the flute players, he (being deaf) is not able to follow the music played by other flutists to the dead (hence 死人笛) and chooses to play on in his own way.
As this second part 唔聽佢支死人笛 was rather long, it has been shortened first to 唔聽死人笛 and later to 唔聽笛. The latest version 唔聽笛 sounds very close to another phrase 唔聽趯 which means "refuse to be at sb's beck and call", 唔聽笛 thus acquires a new meaning of "not complying".