That is a fascinating article and experiment, although it doesn't surprise me that most people gave up their seats. If I were on a subway and somebody asked for my seat, my highest-probability hypotheses are that they have a physical condition that isn't immediately obvious, or that they're just weird. In the first case I should obviously get up, and in the second case it's not worth trying to determine if they'll have a negative reaction if I refuse.
That was an interesting article indeed. I figured I'd just post the title so people have some idea what they're clicking on.