In my business, we have someone prepare the work, then someone checks the work, then someone approves the work. If after all this we find we have made a mistake, then we commit to fixing the problem at no cost to the customer (and we do not cancel orders)
Call it ethics, integrity - whatever you like. However we would honour the customer order.
It does teach you to be carefull from the outset - but you do get kudos from the client for standing up and taking control of the situation instead of wimping out of the deal.