If your daughter is in CA, and most ladies rushing had recs, I'd guess it was USC. I'm sorry she didn't have a positive experience at recruitment. She's got a wonderful attitude.
The office of Greek Life may have a list of women interested in COB to circulate around to the sororities. She can call the office of Greek Life, as has been suggested by other posters, to inquire. Also, she should definitely get involved at the school to make friends and enjoy her freshman year! She may also meet sorority women this way. It's good to have "connections" and network-- these sorority friends may invite her to COB if they hold one. She should express an interest to her sorority friends at an appropriate time so they know she would be open to the possibility of membership.
If your daughter is at another CA school, it just depends. CA schools tend to have a laid back recruitment. UCLA is on the quarter system. Most of the chapters recruit once a quarter. Their formal recruitment is frilly, but COB is not.
It won't be impossible for your daughter to get a bid as a sophomore at a CA school, provided she maintains a positive reputation socially
and academically this year. There are some diminishing returns the closer you are to graduating, however.
Good luck to your daughter. If she is truly interested in Greek Life, she will find the resources to join. It may also mean she joins a sorority that was not her instant first choice. Do remind her that recruitment is but a week of first impressions-- and hasty ones at that. She may rush this spring through COB or in formal next fall and have a completely different take on the process, the members and the various organizations after a year or a semester of living among them on campus.
The best thing for her to do now is to live her life, get good grades and have a good time

Any chapters having COB may advertise it as open to all or do it by invite only or a combination of the two. Again, she should affirm her interest with the office of Greek Life and to any sorority friends she has so they can be on the lookout for her or invite her to their events, if they would like to. Most sororities who can will likely do COB right after formal, and then wait again until spring. A lot goes on with sororities in the fall, so there isn't time or interest in marshaling the troops to take in a few girls right around initiation time. There are too many other activities happening around campus, including fall academics, homecoming, the current new member class, the social calendar, football, other activities, etc.