Yeah never tried it either, can't be bothered about fuel, the cheapest here is about 1:19euros/Liter, I always full it up at an unmanned (sp?) station, that's always cheaper.
The other day I stood next to a girl with a Renault Twingo (small car) and I was looking around while filling up the car and I saw the exhaust of that car, just normal petrol exhaust, nothing wrong with it..then I saw she had the black handle! That's diesel! So I said "your car is petrol right?"
She: "Yeah, it is"
Me: "But you're filling it up with diesel now"
She: "Yeah, you're right..oops", well I could fill it up now, it's already in it right?"
Me: "Yeah whatever bitch" and I drove away..
That last thing didn't really happen..I told her to call the "Service guys"]
And she still didn't get it, she wanted to drive it to the garage...