They're definitely checking randomly, I'd bring a copy of your utility bill (or lease agreement), that is the typical gold standard (any utility bill -- PG&E/SDG&E/SoCal Edison, your local water district, Cox/Charter/Comcast, a wireless bill with a local billing address, etc...) -- if it's cumbersome, consider a digital copy. Are you here for work? I've seen work IDs work (as long it's obvious it's California, like it saying "Google" won't work because they have offices in NY, etc...)