I do double check that the dock hand understands "diesel". Sometimes it's the dockhand who asks me to repeat jus to be sure.We are a bit obsessive on the subject so even have a check off system to force us to double check the pump and then to double check the fill. Being handed the nozzle only half takes the dock hand out of the equation as it could be the wrong nozzle and the wrong pump turned on. Definitely a good way to ruin a day and many more days.
Years ago someone accidentally put diesel fuel in the underground tanks for filling the (gasoline powered) trucks. A lot of people got towed in that day.