Many, if not most, people in that age group actually aren't yet fully vaccinated - the general availability was April 14th in SF. 21 days between vaccines plus

Many, if not most, people in that age group actually aren't yet fully vaccinated - the general availability was April 14th in SF. 21 days between vaccines plus two weeks of waiting. Plus a few days to find a slot maybe. So a few more days... I think it's fine to still not wear a mask in the scenario you describe, but... Fwiw, around here (inner Richmond), there's plenty people without masks. The cafe I can see from my office (if I peek above the screen at least :() has unmasked people eating outside without conflicts for months. Golden gate park is full of unmasked people lounging around.