Thoughts on technical details:
The result of the vehicle registry query is a DID that is assigned to the car. That DID is resolved to a DDO, which contains a service pointer to the car’s Agent. A message is sent to the car’s agent via an Agent Extension. This message contains the offer for the individual in the car.
If the user accepts the offer, the user generates (or reuses a previously generated) DID, and atomically approves extensions for access. This DID is unique to avoid correlation. This new DID is transmitted by the car’s agent back to the shopping mall as an introduction.
The Car’s Agent is sent a signed token used to allow access to the VIP parking area.
The User’s Agent is now communicated with to provide the above scenario.