California wants to stop companies from retaliating against customers who leave bad reviews. Last Tuesday, Governor Jerry Brown signed a law that bans them from adding non-disparagement clauses to their terms of service. Such clauses could let caterers, hotels, or other businesses fine customers who write negative reviews on places like Yelp and TripAdvisor. While its not unusual for employees to sign a non-disparagement clause, its not clear how common this practice is for customers. …