I've worked quite a few of these scenarios as well. The carnage is real. The cost is immense to clean up/make right. I had a site that dropped 7k gallons of Premium into a ULSD (ultra-low sulfur diesel) UST (underground storage tank). They found out about the mistake when 2 commercial trucks (one brand new Volvo and a low mileage Kenworth) died an awful death out on the highway. It takes a pump truck or two to evacuate the mixed product from the UST, a crew of knowledgeable techs to get the tank/lines purged/cleaned, and dispenser filters changed. Think of how many vehicles get damaged, the down-time for the c-store, the reputation of the c-store and chain, cost of techs on site, cost of clean up and turnover. Bad day for the loading rack in this particular situation, as they failed to divert the correct product to the transport. OOOPS.