My experience with this no-cash signs was only on owner operated shops. Maybe I was being an asshole, and they were being assholes to illegal immigrants that can't have bank accounts, and maybe we are all assholes but I really don't care. What I do care is about being able to buy stuff anonymously and without banks or the government getting in-between me or my friends and our food.

Any place big enough to afford having retail employees that I've been to in SF was always still taking cash.