Oh its about safety of the precious baby now is it..
Buses aren't safe. No seatbelts, no tie downs for prams/chairs/whatever, loose stuff.
In a bus crash, passengers are at risk.
Don't get on buses with a baby is safety is your issue.
You ever stop to think why many adult wheelchair users are out with an able bodied person?
Firstly, we are a minority, the chances are that person is a friend, relative or partner - not a carer.
Secondly, if the world were a little more accessible, and a little less entitled selfish arseholes were in it... some of us would be able to do far more WITHOUT requiring an adult, able bodied person to accompany us.
Mummymummy, you seem to be under the mistaken idea that people who can stand and take a few steps can do so without pain or discomfort, safely, easily, repeatedly - this is very rarely the case.
Most of the 'young and very fit' people in folding chairs are those who have spinal injuries and cannot walk at all.
Most of the 'can stand/transfer' people are those suffering chronic long term pain and health conditions that mean they should avoid standing/transfering because its doing them further damage.
But you obviously know best and hey, all cripples have someone with them at all times to supervise, lift them, magic up spaces... and no, we have NO idea at all how hard it might be if we got kicked off transport, can't get on transport, can't make connections... None whatsoever. Public transport for wheelchair users is a fucking BREEZE, truly it is.