American police officers do not like being filmed on the job. To get a sense of just how pervasive this sentiment is, you can (and should) spend a few minutes on Photography Is Not a Crime, a blog run by photographer Carlos Miller.
Over the last several years, Miller has documented numerous cases of American cops overreacting to being filmed. They've arrested people. They've beaten them up. They've illegally confiscated cameras and made bogus charges. Following these rules while filming the police can reduce your chances of getting roughed up. But ultimately, some cops are going to take offense regardless of how polite you are. Canadian cops aren't a whole lot different.
Officer Mark Morelli of the Hamilton Police Department in Hamilton, Ontario, has proven a welcome exception to the rule. A video of Morelli arresting a woman who clearly doesn't want to be arrested has gone viral. It's not because of how the officers conducted the arrest, but because of what happened afterward.
For the first few minutes of the video, Morelli and another officer forcefully arrest a young woman and then place her in a police cruiser. Bystanders criticize Morelli and his colleague. After the woman is in the car, Morelli turns to the crowd. Instead of threatening to confiscate their phone or arrest the people filming him, Morelli takes a few minutes (starting at about 4:30) to explain how and why he did what he did:
Police officers aren't required to explain arrests to bystanders, but Morelli chose to anyway. He talked about what techniques he used and what he'd been trained to do, demonstrating not only that he understands use of force, but also that he wants the people he's working for—those bystanders—to understand it as well. Most importantly? He felt comfortable explaining this all on camera, in what was arguably an emotionally charged environment. That's quality policing.