Believe it or not, this doesn't happen in Seattle. Sure there was a month or two when people were treating bikes like shit, because they were new, but now the conventions have been established and people are more respectful. What you're worried about happens rarely in Seattle.
Assuming you live in SF, I'm not sure why you're not worried more about the people peeing on your wall, tossing their shoes or random garbage on your driveway more. Bikes being dropped off at a public sidewalk sounds like less of a problem than these.