I cant understand either why parents do this.
If you have a car with airbags installed it even states that you do not place a child under the age of 12 in the front seat as when the air bag goes off it can be fatal.
We use to have a sports car that had hardly any back seats and my husband, who loved that car smile, decided that it wasn't safe, and the baby seat didn't fit, so we now have a 4WD. Deffinately helps when you have 2 kids stills in seats.
It makes you wonder why people do this, and not install the car seats correctly, and if bubs needs a feed then pull over.