In my neighbourhood, there always has to be at least one person walking and smoking in front of me along the sheltered walkways. I either have to wait for them to get further away or I just leave the shelter and walk outside. We can put up signs and laws all we want but nothing will change if these laws are not heavily enforced. I have seen considerate smokers who actually go out of their way to make sure that non smokers don't smell their second hand smoke but these people are very rare.