The last time I saw an obese person get on a bus, they managed to get through the tight gangway from the entrance to the area where the wheelchair and buggies use, not an oversized Chelsea tractor buggy who has to use the middle door to get on the bus in the first place.

For the record I have nothing against parents and their children using public transport, it's the fact they feel they have the right to use space allocated to disabled passengers, which is why we have low floor buses in the first place.