I noticed this in Beijing in 2007 (I'm a wheelchair user, so I'm looking at the sidewalk a lot). Here's a photo of one of those bumpy yellow paths leading straight to a steep flight of stairs under Tiananmnen Square! I've always thought back to it as a perfect example of things people try to implement in order to help disabled people but that have the opposite effect of help. Anyway, a good example of a well-meant but bad user interface!