Sales Quote Line Item Cancellation

I recently took a training for users on GP SOP. Training was a success. There were couple of users who are already into GP for quite sometime now (4 years precisely). Interestingly, when I was explaining about Quantity Quoted Vs. Quantity To Order Vs. Quantity Cancelled , one user said they had never used Quantity Cancelled at all to record any line item cancellation. That was quite a surprise to me. Consider this scenario: A customer enquires about couple of products and we prepare a quote and send more