I am just not reading through this thread and I'm amazed at the number of losers who are not willing to give up their seats for a pregnant woman or an elderly person. I have been to Disney pregnant and it was about half the time that someone gave up a seat for me. But everytime I am on the bus I give up my seat to someone that needs it more than I do. Especially people with small children. What do you suggest people with babies do? Hold the baby and hold onto the railing above.
I think these people who don't give up theirs seats are pathetic. What goes around comes around. It plays into the whole entitlement mindset that many have at Disney. "I paid good money so I deserve something free and I deserve to ride every ride with no wait, and I deserve to have a seat on the bus" And all kindness and decency goes out the window.
Judge much?
Expecting everyone to jump out of their seats that they waited for is pretty rude and pathetic by itself. They waited their turn (isn't that what we've all learned at Disney? How to take our turns for a ride?) and now they're reaping the rewards of doing so. You (in general) coming in and demanding a seat they waited for is a pretty rude gesture.
There are other options, and if you think standing on a bus is going to ruin your trip, then it's not worth it to risk having to stand on a bus. Rent a car, take taxis, hire a personal driver (ok, that one is a bit of a stretch

). Planning ahead to avoid the situations is just as important as planning ahead to take advantage of what the world has to offer. If that means that you leave an hour early, so be it.
Now, this tirade may make you think that I sit down and guard my seat with fervor. Nothing is farther from the truth. I stand when the bus is full. I stand because I can, am able, and willing to do so. It doesn't make a lick of difference to me who else is standing along with me and who is sitting. I'll offer my seat to moms, dads, kids, gramma, grampa, cute girls in the 25-30 range (ok, there may be ulterior motives with that one

), it doesn't matter to me. Only once has it been bad, and that's because I forgot to go before I left the park... (the mad dash back to the room was pretty funny, I'm sure

)
So, calling others losers and pathetic when they won't give in to your demands, when they waited their own turn, is pretty bad. You'd be much happier just worrying and taking care of yourself and your loved ones than worrying about what other people do.
Now, there's also a difference between appreciating an offer and demanding one. I'll let you figure that out though
