What a load of BS. Is this law up for a public vote?
Tell people you're taking their dogs and cats (and other pets) away and you'll have a mass exodus or hopefully, riots.
And what is the deal with banning everything except fish? If these people are worried about mass animal abuse, FISH (the only pets allowed) are the most abused & poorly cared for of all animals Goldfish in particular are generally doomed on a monumental scale, - far more than Hamsters this law seems obsessed with. If we're running a death tally you could never stop counting the dead ornamental fish.
As for the hamster dilemma Just get some big snakes for the pet shelters and feed the reeking little things off. Problem solved!
However, the kinda pets a lot of us partake in don't come from a pet shop anyway. Though this would screw over any of the few and far between quality reptile and insect shops. Don't know if there are any in SF but there never could be either.