The reason is that there is no one to stop them doing it. There are no police about, so they know they can get away with doing it. This is the problem with society at the moment and all the little shoots in london running around with knives etc. They start off doing minor things and then as they don't get stopped or punished, they do more things and increase the level of crime.
I belive i have worked out now why i have the camera. If i, a little cyclist doing my 7.5 each way ride can spot at least 1 person every jounry with no seatbelt, on phone, going through red, then why the hell are the police not doing the same? if they are out there for a shift, they should be stopping loads of people, hence there would be less people commiting those minor crimes and we would see less on the camera. And i'm sure if you stop some of these little shoots in their illigaly blacked out windows with no seatbelts on, your going to find other crimes like weapons and drugs. make sense? rant over.