My DS is 27 months old and as I am 33 weeks pregnant I decided a few weeks ago that I wasn't going to carry him up the 3 flights of stairs to our flat. In the past he had mostly walked up, though if he was tired then I would carry him.
He responded well at first, and is still fine if he is sufficiently distracted (by one of the the neighbours coming in or our, by something exciting that we are going to do when we get in or out) but we quite often have a huge power struggle with him refusing to move for ages (sometimes takes half an hour) or playing dangerously. The issue isn't about going up or down the stairs anymore, it is that he has realised that he can wind me up by not moving. There is very little I can do because it isn't safe for him to go up or down on his own.
Just bought some stickers to make a reward chart. Any other ideas?