IBshipment- setting Over Receipt Warning or error % in the IBShipment UI

Summary:

There was a stance that the PO got linked to the shipment at the time of receiving and therefore, while receiving the item from the PO , system considered the shipment and added the receipt record under the shipment. The item was not part of shipment but got received in it. The system did not show any error or warning message of Part not on shipment".

Content (please ensure you mask any confidential information): What is the way out of prohibiting such transactions/scenarios in future? How would setting over receipt error % or over receipt warning % in IBshipment UI help in this?