Did you travel in Europe? Even without crisis, gas stations are often way busier on the cheaper country's border than more expensive.

My friends living in Switzerland (near the border) always go to Germany to fuel up. And, even without a crisis, gas stations on the cheaper sides of borders are often way more crowded than on the other side.

Also, keep in mind that Slovenia is roughly the size of Los Angeles. Or not much wider than Long Island. If there fuel was 30% cheaper on one side of Long Island, than on the other, I'm sure plenty of people wouldn't think twice about that.