If the dog ban is a public-safety measure, why does it include exceptions? Dogs and their owners have also been attacked in other  parts of town by dogs living with their housed owners. Why not ban dogs everywhere in the city?
If the smoking ban is a public-health measure, why are there exceptions for bar patrons?  Bar patrons smoking outside of these establishments create just as much second-hand smoke as anyone else. 
These bans will be enforced lightly for people who don't fit the profile of homeless people, but they probably will be strictly enforced for those who aren't as well dressed.