Yes, it knows which packages belong to you. It will only unlock if the package is being delivered to that specific lock and the package is "out for delivery".
This is probably the biggest roadblock to this product's success. However BoxLock is in talks with all the major carriers to provide training. The carriers themselves are incentivized to use BoxLock because it provides a guarantee that the package was delivered successfully and securely. They don't want packages stolen either.
You can add delivery instructions to most shipments that tells the delivery driver to use BoxLock.
You always remember the successful investments you didn't make, but not the unsuccessful ones. Think of all the money you didn't lose making bad investments.