"Patrolling" is pretty vague, the concern is primarily about groundless stopping, searches, arrests and shooting of suspects. It is discrimination if e.g. groun

"Patrolling" is pretty vague, the concern is primarily about groundless stopping, searches, arrests and shooting of suspects. It is discrimination if e.g. groundless searches are done at higher rates on people with a certain ethnicity, since presumed innocent individuals of any ethnicity should be treated equally and with the same rights. Stopping cars just because of the skin color of the driver is not "perceived as racist", it is racist, since you are treating people worse due to their race.