It’s illegal to charge for a job interview in California but actor workshops have always skated right on the edge of legality. They are technically not job interviews, because CDs will tell you they don’t hire from workshops. Parents of actors, if they are being truthful, will usually say they paid big bucks for workshops with casting directors because the expense is worth it if their child is hired by that CD for a job.
The Los Angeles City Attorney’s office has wanted to prosecute acting scams for years but they can’t without victims and most “victims” don’t want to follow through. That may change as they have put out a call to the casting community. Read about it here and in the Hollywood Reporter.