The party that lost one of my smart keys has promised to pay to replace it (yes, they know it will be expensive). However, is there a way to protect my Prius from the possibility that the "lost" smart key might turn up someday in the hands of someone who might try to steal my car?
The car is associated with the key, not the other way around. The dealer should be able to remove the current association. Tom
The car can "see" any Prius fob, however it will only open for ones that are authorised. When you go in to get the car programmed to recognize the new fob ask them to clear any other fobs besides the one you still have and the one you are getting. An attacker could still use the metal key part to open the door, but they're not going to go for a drive. Not sure what the rest of security system would do.