Pepper spray and tasers are in increasing use by both police and military, and more exotic non-lethal weapons such as heat rays are in the works. At TEDxCanberra, ethicist Stephen Coleman explores the unexpected consequences of their introduction and asks some challenging questions.img src="http://feeds.feedburner.com/~r/TEDTalks_video/~4/mr29AtOMMtI" height="1" width="1"/