I think you're doing just fine. It's the same way with many old women here in Japan (for some reason the old men are much calmer, more relaxed, and don't cause troubles for anyone). I had a women almost kill herself rushing to get in front of me in line at the super market (http://www.imbermedia.net/users/darintenb/blog/?postid=8 Japanese only), but I can guarantee you she is the same person that gives you the stare on the train/bus.
They call them priority seats here, and they're for everyone to use, they just give priority to those who need them most like elderly people, injured people or expecting mothers and things like that. But if grandma is clearly training for the olympics, my original bad knee's take priority to her recently replaced hip.

I do not have this problem as I am normally fooled by their cunning disguise into thinking that they are in the full flower of youth and probably younger than me. My big dilemma comes when trying to assess whether someone is 3 months' pregnant or just generously built.

The question is do the dye-haired elderly get up for you, Dave?

phizackerly: In Japan, being overweight seems to be enough of a social disability to warrant being given the priority seat, so either way I think you're safe ;)

I hadn't thought of that before now, Dave, but now that you mention it I think you're right. If they don't want to be viewed and treated as elderly, I can't see anything wrong with obliging them (though perhaps not in a way they'd like). I ride the bus to and from college every day, and I normally do move for the elderly. But if I ever find myself in that position with an obvious hair-dyer, I'm going to pull a Dave.

I do not believe in giving fatties seats. They need the standing-up exercise.
Re the dyers - I don't know about men, but some women think that they look unkempt with greying hair. It's not a youth thing - it's more like: I may no longer be young, but at least I can be well-groomed.
I don't dye, but then I am a scruff.

To answer these questions, first off Simon they have never gotten up for me, even when I was in a cast. But I don't really hold that against them, or certainly less than other able-bodied people that pretend they don't see me, or perhaps are simple so inured to not getting up that they weren't aware of me.

I will give up my seat for 6-month pregnant ladies, but yes, it is sometimes difficult to tell with pregnancies that are not yet so pronounced.

I actually had a chance to prove my strategy yesterday when a dyed-hair old lady stumbled onto the KCR last night as I was making my way back from Lo Wu. I was panicking, as she was clearly tottering. Providentially, though, the person next to me leapt up and off the train (having almost forgotten her stop) and the old lady was able to sit down next to me.:)