Specifically how much info do you have to give cops

Scene: Cop drives into a neighborhood. Child sees cop, starts running in opposite direction.

Should the cop:

A) Chase the child to find out why they’re running.
B) Go about their merry way.

Scene: Cop drives into a neighborhood. Group of people talking see cop, stop talking, stand absolutely still and stare at cop.

Should the cop:

A) Ask the group to find out why they’re acting suspiciously.
B) Go about their merry way.

Scene: Cop drives into a neighborhood. Group of black people talking see cop, stop talking, stand absolutely still and stare at cop.

Should the cop:

A) Ask the group to find out why they’re acting suspiciously.
B) Go about their merry way.

Scene: Cop drives into a neighborhood. Sees a black person driving an expensive car.

Should the cop:

A) Stop the person to find out who owns the car.
B) Go about their merry way.

C: Shoot the Kid

If you think that is what I meant by “appears nervous”, I really don’t know what else to say.