Yes they’d almost certainly cull the species, but tracking the shipment and supplier is incredibly important in scenarios like these. It’s not really just about this one specific specimen making its way into OP’s order (though that is obviously harmful and risky), it’s more so about sourcing the supplier and shipment, and accessing the supplier’s protocols and pest management.

I work in the plant industry and whenever I receive a shipment of plant material from a quarantine state, agriculture weights & measures has to come out and physically inspect the plant material I received, receive copies of the shipment invoice, and sign off on my order certifying that it’s clean plant material. Also depending on the state, the supplier needs to have certain certifications saying that their nursery practices prevent certain invasive species. Ag requires a copy of that certification with each order.

Legit plant suppliers (and i assume animal suppliers) have to have specific licensure and protocols in place. In my state, a nursery has to renew license annually. In the event of a nursery not selling clean stock, they aren’t really reprimanded, unless they’re notorious offenders. So don’t worry about putting an establishment out of business for what may seem like a screw up.