In San Francisco, the Society for the Prevention of Cruelty to Animals (SPCA) was using a 181-kilogram (400 lb) Knightscope K5 security robot to patrol the streets around their campus in an effort to prevent the homeless from sleeping or loitering there. The SPCA believed that the robot was reducing crime and needle debris around their campus.
However, the K5 angered a lot of people who felt that this was an unfair attack on the homeless. The robot was knocked over, veiled with a tarp, and had its sensors blinded with barbecue sauce. Someone even smeared feces all over it.As of early 2019, hiring a robot for this job appeared to be more cost-effective at about $6 to $12 an hour than the minimum wage of $15 per hour for a human in San Francisco.