One of the maxims of capability-based security is: “don't prohibit what you can't prevent”. If I give Alice a capability, I can no more prevent her from sharing

One of the maxims of capability-based security is: “don't prohibit what you can't prevent”. If I give Alice a capability, I can no more prevent her from sharing it with Eve than I can prevent her from being a proxy for Eve. This makes capabilities a more honest form of systems security.