If the operators are careful never to travel to California, does it end there? Would a California judge order ISPs to block particular sites? Could payment providers be forced to stop paying?
The state of California has extradition agreements with other US states. The article says that the owners of the site are living in other states in the US. So they will simply say to those states, "Hey, these people have been convicted of a crime in our state. Please collect them and send them to us." The other state will likely comply per their agreement.