Maybe because the 18 people scared of being sued by the little girl's parent for knocking down their child?
http://www.whatsontianjin.com/news-1...ide-court.html
However, where is the little girl's parent or guardian? Why are they letting a little girl cross the road?
Or in my place, if you stop to help, you'll be beaten up by the person's family members and relatives and distant relatives and so on and so forth. Because it's clearly you are the one who knock down that person... Strange ain't it?