CouthyMowWearingOrange I very much agree with you expressing your need for both yourself and your DS2, and applaud it.
I would instantly give you my seat if I heard your request.
In this text form at least, I can say that to me at least, you do project a very loud and demanding voice. This is not a criticism, and I beg you please do not take it as such.
But you may well be expressing your need more loudly than you realise you are, which can in turn make people feel a little defensive and fearful ('gets their backs up'), and you may receive a more hostile reception than you deserve.
Miscommunication all around I sincerely believe.
Even if you approach 'politely' at first, the anticipation of a rising situation may be at the back of your mind, and may make even your polite attempt seem aggressive to the receiver.
Your personality in general may come across more strongly than you mean it to, and may intimidate others so that they react aggressively/rudely.
Please understand that I am not expressing any criticisim at all, just 'saying it how I see it', and seeking understanding.