I have to confess that I feel a little sorry for smokers. They are told to smoke outside, XX number of feet away from any door, yet there are no longer ashtrays for them to use.
Trash cans are not safe places for cigarettes. Sometimes the smoker has stepped on it and really thinks it is out, but it isn't.
But don't remove all the ashtrays and then admonish them for leaving their butts in the street/on the sidewalk. There need to be options available and when the bans prohibited smoking indoors, the number of outdoor ashtrays should have (if anything) been increased, not decreased to zero!