Why do parents buy teens cell phones?

If used responsibly it is a wonderful source of information. Imagine when you were a child and a thousand questions came into your head a day. How does this work? Where does electricity come from? etc. By the time you got home you had forgotten all about it. But imagine you could find out the answers on the spot or when you were sitting on the bus or waiting for a lift. It is a wonderful educational opportunity. It just needs to be carefully monitored and ground rules need to be set as with any other form of ICT.

Basically because the parents just give in to their children when they keep on nagging them about getting them a smart phone.