Reports the order's guest data completeness against the guest data requirements configured for each product's ticket category (see the Ticket Category Details endpoint's guest_data_requirements property). The response contains one object per product on the order, each listing — per guest — the guest data fields still missing. A product whose requirements are fully met, or whose ticket category has no requirements configured, is returned with complete = true and no missing fields.

Missing guest data never blocks an order; use the update order guests endpoint to supply it.