Like carjacking or joyriding, only hijacking an unsuspecting person instead of a car. The term was invented by Chris Morris for the 'Crime' episode of Brass Eye. It was a popular pursuit in the fictional, crime-ridden estate of Coswick. The git surfer creeps up behind their victim and jumps on their back, forcing them to run around at 'terrifying leg speeds'.
They hijack pedestrians and run them around a terrifying leg speeds. It's called "git surfing", all too often, the "git" is one of their own mothers