Well Dave I'm always doing that too, and it's always a great success. People are thrilled to be able to talk to someone who seems interested.
I think these young mums with their unfortunate sprogs trapped in their pushchairs are basically a bit lonely, and use their mobiles as a form of substitute company. They roam round the city looking at clothes because they haven't much else to do, and haven't the sense to take Junior to the park and play with him.