I must say this. When you say children should give up their seats for 'grown ups' please take one moment and think - is that child able to stand for a, what might be a longish journey.
When my brother was around 6, I was travelling with him and my mum on the bus. My mum always put my brother by the window and she sat on the outside seat. A very self important man said to my mother that my brother should give up his seat for him. My mother looked at the man and said, ' you look fit enough to me, in order to stand.' then the man started to lecture my mum on not bringing my brother up properly!' My mother said the man knew nothing about my brother and then opened my brother's shirt to reveal a scar that went from the centre of his chest and went round under the arm and across his back. My mother said he has only a quarter of his lung, cannot stand or walk for long and has not long come out of hospital. the man apologised but is showed he just didn't think about anyone than himself. Children are obviously supposed to be A1, never be ill, would never have serious problems.
My brother has fought all his life to be as well as he can and a lot of times he has had to be hospitalised due to breathing problems. He has worked all his life, has a wonderful family, despite his health problems got a good education, but is now having to visit the hospital more often.
Would you know if a child had Junior Rheumatoid Arthritis, breathing problems, was deaf, was asthmatic, had other debilitating illnesses that are 'hidden illness'?
Three out of my five grandchildren were born prematurely. One has lung problems as a result of being premature. The twins have problems with their ears.
I might be a bit tough on you but you cannot lump everyone in one box. If you are so knackered you need a seat, you can reserve a seat, or ask the parent/guardian of the child if they are ABLE to stand and let you have their seat. That way no one will be embarassed, annoyed, upset, feel threatened. My brother wasn't able to stand up for himself we had to do it for him, my mother didn't want to get angry with the man but he was agressive to her.