For me, during my pregnancy, most of them gave up their seats for me, be it reserved seat or normal seat. But, still got some people pretend to "never see me"...
MRT still not so bad, cos got the reserved seat sticker. Bus is worse...not even once I was offered a seat.
Usually, if it's a short journey, I'm prefectly ok with standing. But, to stand from Bugis to CCK, is a long journey... There was once I was carrying my daughter (5 mths old) and the train was packed. I walked to the reserved seat and guess what? The woman immediately shut her eyes and pretend to zzz. The next thing I did was "can I have this seat? It is reserved for those who are carrying baby." She pretend not to hear. So, I raised my voice and vola, she gave me a black face and stood up.
For me, since the seat is being reserved for us, we should fight for our rights. And, if someone refused, I would tell him or her that the seat is "reserved" in the first place for certain people and that they are not suppose to sit. I even have my IPOD tuned to the meaning of reserve / priority - just in case some people wants to argue on first come first sit basis.
However, so far I've not encounter anyone that dares to argue with me on the reserved seat.
Do you know in HK and Taipei, those seats with reserved usually are not occupied - even in peak hours. Or, they'll give up their seats automatically...