As most sites are tied directly into an MIS via an integration, having a webhook that would trigger when an order is deleted would be useful to update the order in the MIS as needed. The event in the MIS (depending on the MIS) could also trigger a notification flow so any key stakeholders knew the order was deleted.
The webhook Payload could be very simple, most likely would only need the following:
Order#
Order ID (the guid)
site name
sited ID (the guid)
Datestamp of event time
subscriber ID (guid)
This would also be very useful during testing and setup of stores, allowing the orders to be tested and then deleted out of Pressero and the MIS when deleted in Pressero.