On both my mk1 Fabia and Octavia, it was possible to vent the fuel expansion tank to get an extra few litres in to the tank when filling up.

Obviously not the smartest of ideas if you're going to full up and park in the sun, but not bad if you're about to embark on a long journey or want to maximise the benefit of your Tesco 20 pence per litre discount...

Does the Yeti have an expansion tank, and if so, is it possible to vent it to squeeze in another tenner or so of fuel?

I wondered that too.

Always used to vent my Ibiza and Passats, but haven't seen any such nipple in the Yeti...