New FBA Inbound API v2024-03-20 - What happens if you "cancelInboundPlan" on a completed shipment?

[MetaMan2023]

If we create a shipment plan / shipments and then call cancelInboundPlan, does it always cancel the shipment or will it throw an error if the shipment has reached certain status? We don't want to test this on a real shipment that has been completed but are curious if Amazon has protections in place if it's done by accident.

Examples:

• What if a shipment has had placement options, transport + delivery options confirmed (but not left the building yet)

• What if the same as above, but is also tracking as in transit, received, etc?

• What if a shipment has actually tracked all the way to Amazon and inventory received?

Are there any situations where Amazon will throw and error and not cancel the inbound plan, or is it absolute and we have to be careful to check statuses and handle on our side?

-John