People have a legal location of residence in the US.
In California, if you're homeless, you typically have to set your mail up as "general delivery" to your nearest post office where you go to collect mail every few days. You probably don't have any other address.
Not sure how this interfaces with this specific law otherwise, but using a post office isn't a bad idea generally because it isn't a totally unexpected thing. A homeless person would probably list that as an address.
There's also a lot of mail services that will give you an address in that state and will open/scan received mail for you... not sure if California specifically has one, though. But yeah, this doesn't establish legal residency at all, but many entities don't look too closely either... might be worth a shot.

Not to mention... do they think bots on windows don't exist?