Gracious NO.
What exaclty is it about your random pregnant woman, child, or older person that makes them so fragile?
When pregnant a woman's center of gravity changes making their balance "quirky" and more likely to fall.
When I was pregnant I HATED sitting down. To sit meant pain on standing. If I had decided to go to Disney then, if I had felt strong enough to go, I wouldn't have wanted that pity from anyone.
That sounds awful! I feel sad that you find this pity.
And kids are like bouncy balls.
Really?
It's just so insulting to see fragility in that group of people.
Again, I'm not sure that people are assuming fragility.
I won't sue you, but I will feel judged and insulted by archaic notions that because I have XY chromosomes I'm weak and frail and fragile and can't stand up.
First of all you have XX chromosomes if you are a female.

Second I used to feel similarly when I was younger, I'm only 41 but I feel much more like it is a kind, loving, gracious thing for another member of society to do for another that they think need the seat more than they do. I used to feel judged by that, not anymore. I'm not sure what changed, perhaps its the fact that I was diagnosed with RA when my 8 year old was an infant or that I'm older and not as angry as I used to be.