The bonding agent (the Surety) sets the bond rate based on the perceived risk of the venture.
Unbonded ventures are not permitted to operate. In a telco context, unbonded carriers would not be peered to other carriers.
Overview of how surety bonds work: <https://www.suretybondsdirect.com/educate/what-is-surety-bon...>.
California's present regulation: <https://oag.ca.gov/consumers/general/telreg>