What API and data model would support a new AirCover workflow for group travelers

Problem Statement Description

Product context: Airbnb is a travel marketplace connecting guests and hosts; its products include stays, experiences, host tools, guest booking, trust and safety, payments, and reviews.

Airbnb wants to extend AirCover to better support group travelers when something goes wrong during a shared trip, such as a listing issue, safety concern, host cancellation, missing amenity, check-in failure, or need for rebooking support. Today, AirCover workflows are typically centered around the booking owner, but group trips often involve multiple guests who may coordinate, pay, arrive, communicate, and experience issues differently.

You are asked to think like a Technical PM and define the API and data model needed to support this new group-traveler AirCover workflow. Focus on how Airbnb systems would represent the trip, group members, roles, issue reports, eligibility, evidence, communications, resolutions, reimbursements, and state transitions across guest, host, support, trust, payments, and messaging systems.

Your answer should clarify requirements and trade-offs without jumping straight into implementation detail. Consider how the workflow would operate globally, across mobile and web, with privacy, abuse prevention, auditability, reliability, and host marketplace health in mind.

The experience should consider:

- Core entities and relationships, such as reservation, group, guest roles, AirCover case, issue type, evidence, resolution, reimbursement, and support interaction.

- API surfaces needed for guests, hosts, customer support agents, internal trust systems, payments, messaging, and notifications.

- Permissions and privacy rules for who can create, view, update, escalate, or resolve an AirCover case within a group trip.

- State management across claim submission, validation, host response, support review, rebooking, refund, reimbursement, closure, and appeals.

- Data integrity, idempotency, audit logs, fraud prevention, and abuse controls for high-stakes support and payment flows.

- Reliability, observability, error handling, latency expectations, and rollback considerations for a global travel marketplace.

- Product trade-offs between fast traveler protection, fair host treatment, operational cost, and marketplace trust.

The goal is to describe a technically sound product foundation for group-based AirCover workflows: what needs to be modeled, what APIs should enable, how systems should interact, and what constraints must be handled so the experience is trustworthy, scalable, and safe for guests, hosts, and Airbnb operations.