It's an interesting idea, but I have no clue how to establish a person's residence when they don't have a street address to receive mail, utility bills, etc. Practically by definition, the homeless do not have residence.

People who recently have become homeless would qualify, assuming they could provide mail or something from a year ago, but even that seems like a stretch for most people, I think.

Also, I don't know about SF, bit quite a few of the services provided here in the Midwest are privately run (I.e. in association with churches or otherwise non-profit), and I don't know that such a ban could be imposed on them.