I get called one at least once a week.
I've found people will drop it because they don't get what they want, they want to "scare" you into giving in or they think it's justification for them going to jail/being stopped/cops coming to their apartment/house/duplex.
I've stoppe cars not even knowing what race the occupant(s) are.
Immediatly upon contact its "you stopped me because I'm (insert race)"
I tend to laugh at people when I hear it.