That Lieutenant John Pike, he just can't get enough canvas to graffiti with his scalding, nerve-disrupting Scoville (4 million unit) paintbrush.
Pepper spray is banned from the battlefield. But it is perfectly safe for well trained officers to deploy on civilians. Worse than the Habanero or the Himalayan ghost pepper, and not available to ordinary citizens except at weak concentrations, it is dangerous to the respiratory system, more dangerous than tear gas. It leaves chemical burns, giving one the sensation of being set on fire, leading to bleeding and difficulty breathing even days later.
Knowing that, some trained peace officers force open the mouths of their victims and spray their chemicals, which contain far more than capsicum (the mild heat in peppers) down their throats, strictly in the interest of peace of course.