Bail information is considered public record in the State of California, meaning that anyone (not only defendants themselves) can request this info. The details can be accessed via the Public Access to Court Electronic Records (PACER) system or the Criminal Intake Section.
A surety bond spreads the risk out between the three parties involved. In exchange for the 10% bail premium the bondsman agrees to be responsible for 100% of the bail amount. To offset some of this risk a bail bondsman will usually need you to use some form of personal property as collateral as well.