lunchtime ponder

I was just browsing the headlines on Google news whilst eating lunch. There is yet another article about fat-busting pills and obesity with pictures of fat people walking on the street, taking a dip in a bikini which fits them like a string around a ham, eating a fast food item in such a manner which makes you think "you should not be eating that".
I began to wonder whether these are just random shots of people on the street? Did these people consent to having their picture taken with an article about overweight people in mind? Will they open the paper one day or log onto google news and think "gee, that person kind of looks familiar".
I mean, how peeved would you be? And yet, what fat person in WOULD consent to having their picture taken for an obesity article?
Anyway, I was just wondering. And not for the first time...