Definatly you should have said something. Most places have fines for littering, and weither or not people notice it or not, throwing your cigarette butts on the sidewalk is littering. If you want people to start cleaning up their act and changing the way they treat the environment, definatly saying something will influence it. I mean, maybe you wouldn't have been the first person to say something, maybe you would have been the fourth or fifth person to say something to her that day. That certainly would influence weither she changed her ways or not. A lot of the time people just don't realize what they are doing.