Most of my younger days were spent pumping gas; back in the day they were called Service Stations. Once you take a petrol bath, you learn never stand behind the delivery nozzle of a gas pump while it's in a fill neck. Always stand to the side. That way if you do get blow back, your hand just gets soaked.

The '69's fuel filler is different. I don't have that problem of finding the right spot or speed for fuel delivery. But I do get a little blow back when I'm not paying attention to the sound of the tank filling.