If you want to get into Cal, I would consider any request for supplemental information - whether “required” or “optional” - as an absolute must. It could mean the difference between an acceptance and a rejection - who wants the regret of not doing everything possible forever hanging over one’s head? D was given the “option” to submit LOR’s two years ago when this thing started. I don’t know if she was singled out, as everyone she knows from her HS who applied was given the same option. The only specific condition that would have applied to her was maybe the second one (if this list was in place back in 2015). In any case, she submitted them, was accepted and is currently a sophomore.
Below is a link on study from last year about this topic:
I think the thrust is to see how LOR’s helped or hurt admissions chances for the disadvantaged applicant, and it gives insight into the admissions process.