A few years ago, Baltimore told its police officers to make more "quality-of-life arrests" like New York City famously does. The mayor wanted police to monitor corners known for drug dealing, for example, and arrest people who hung out there for minor offenses, such as loitering or littering, the Baltimore Sun reports. There was a spike in arrests, and a lot of them didn't hold up in court. Naturally, there was a lawsuit, which Baltimore has just settled for $870,000. They've also agreed to retrain officers so they don't make unjustified arrests.
After Baltimore adopted a "zero-tolerance" approach, there was a drop in violent crime, but it only lasted a few years, the Sun reports. I'm not sure how it's held up in New York. I know there have been legal challenges to NYPD's use of stop-and-frisks.