A couple years ago the hose from the gas fill to the tank of my 2002 Hyundai was cut and all the gas drained. I found out when the gas I was trying to pump into the car went all over my shoes.

While not advocating such vandalism, perhaps it sugggests a location to install and inline valve / outlet? I'm thinking you might want to keep this quiet from the manufacturer, your insurer, etcetera.