I'd say about half the times I've filled up on gas for my '13 Mazda 3 hatchback, when the gas shut-off engages, it burps up gas. Sometimes it's just a little that goes over the rim, but sometimes it spills over quite a bit onto the car's finish which of course is not good to have gasoline running down the side. I don't ever top it off, I don't think it's worth it. I thought that maybe I had bad luck, but the last two cars I had (another Mazda 3 and a Jeep Wrangler) I never remember it happening. Has anyone else experienced this?