Recently moved into a new neighborhood in the Berkeley Hills. There isn't another California coast live oak for at least half a block, so they must be transported by more than just gravity or wind. A neighbor walking by saw me pulling a few and commented that sometimes birds drop them. I think maybe squirrels might be redistributing them. I found one under my deck (growing between a concrete tile crack), which doesn't have any reasonable path for an acorn to travel unless it was moved there. I'm pretty sure they're sprouting from the acorns, as the few I've pulled usually have the shell of the acorn attached to the root.
Not sure what to do other than pull them. I tried using 1% Roundup from a spray bottle, but they seem resistant. I wasn't sure if maybe the leaves had to be cut to improve absorption. Once I visited a local botanical garden, and chatted with some of the gardening crew. They commented that live oak acorns distribute everywhere, and lots of their time is spent pulling saplings from the garden. I sometimes hike on trails where the acorns are just everywhere.
We've been having a certain problem in Berkeley with a few planted live oaks that are planned for removal on University of California property.