This is the apt name of a recent protest against a proposed San Francisco ordinance that would prohibit sitting or lying on city sidewalks. Apparently Mayor Gavin Newsom was finally convinced of the need for the ordinance after taking a walk with his child on Haight Street (and claiming to see a man smoking crack on the sidewalk). Hadar Aviram has some interesting thoughts in this post on PrawfsBlawg regarding the sociological and criminal implications of the proposed ordinance. As Rick Hills points out in a comment, the Ninth Circuit held that a similar Los Angeles "anti-camping" ordinance violated the Eighth Amendment's ban on cruel and unusual punishments. I'm less confident in the court's 8th Amendment reasoning than Rick seems to be, but perhaps the decision will convince the council to withdraw the proposal.
I see this ordinance as part of a pattern of governmental displacement of the homeless and other vulnerable groups. We might consider it alongside the recent Arizona proposal to allow police to arrest undocumented aliens for "trespass" if found in the state. As I argue in this piece, these and other forms of "constitutional displacement" use spatial regulation to banish or remove unwanted persons from public spaces.
There are some specific First Amendment implications. This ordinace would become part of the public order management system used to restrict public assemblies and contention. Spontaneous gatherings of a few people or small groups might be chilled or prevented under an ordinance that criminalizes sitting or lying on public sidewalks anywhere in the city between 7 a.m. and 11 p.m. So might panhandling, which is arguably protected speech. If speakers or assemblies are blocking the sidewalks, then police may remove them. (Crack smokers can of course be arrested for that activity.) However, if they are engaging in a symbolic lie-in or sit-in, or are otherwise engaged in expression but not causing any disruption or obstruction, then it seems to me that the state needs a more important reason than "business interests" or "public aesthetics" to prohibit merely sitting or lying on the sidewalks. The public sidewalks are, after all, traditional public forums. Mayor Newsom will just have to share them with the public.