1) If the stars of the film are two cop brothers, one of them will die during the movie.

2) If the star is a cop, and his brother a triad member, they will face up to each other at the end.

3) If a cop is relieved of the case, he will continue investigating that case during his free time.

4) When a cop is temporarily suspended from service, he will give to his superior his gun, badge and a tiny gun hidden on his leg.

5) If a family has a lot of sons, and the father is a cop, all the sons are cops, too (excepting one).

If a cop goes undercover in a triad gang, the leader of the gang will understand him and appear more noble to him than his superior on the force.