Doesn't apply if the parties have notice of the recording. Offer to take notes for the meetings and tell people you're recording for the notes. People making openly racist/sexist statements usually won't refrain when a mic is on-- they do it because they've convinced themselves that what they're doing is OKAY.
Failing that, an illicitly obtained recording can still be used in court in California if its used to disprove conflicting testimony. So you sue over the discrimination, when they lie and claim they didn't say the statements in question, the recording can be introduced.
You'd still be vulnerable to the $2500 fine and imprisonment, but I don't know how likely it is that a prosecutor would actually go after someone for making a recording which exposed a crime. Personally I'd be inclined to get a recording and then decide what to do about it later, since if due care is taken the recording would be unlikely to be known to anyone but you. Obviously you should get legal advice before trying something like that.
This is a very optimistic statement, and I hope you are right, but I'd imagine the probability of a candidate who announced he'll record the interview to get hired will be approximately zero.
Personally, I'd expect the interview cut very short, if not immediately e.g. citing an existing security policy or something.
I've seen many places with "no recording for our client's privacy" on the doors.
