From my experience there are a couple of factors involved.

1. The gas inlets on our cars are very low in comparison to modern vehicles. From what I have experienced on my '67, filling a '69 must be a nightmare.
2. Today's vapor recycling "elephant trunk" fuel nozzles always create a "kickback" affect when they shutoff.
3. Modern vehicles have a restriction just below the fuel cap with a flapper door (left over from the leaded fuel days when leaded pumps had bigger nozzles - so you could not fuel a lead free car with leaded fuel accidentally). So that restriction does a great job of preventing splash back when the nozzle kicks off.

So, you have to use some a bit of finesse on these cars. Put the gas nozzle in as far as it will go, set the "hands off" trigger just once and quit when the nozzle kicks off the 1st time. If you try the "hands off" again, you are going to get gas on you.

If you want to fill the tank as much as possible, you can continue "manually" without using the "hands free" trigger, but if you push it, you will overflow the tank and splash yourself.