There's one 7-11 (convenience store) near my work which has a gas station integrated. It posts as fuel, not groceries, even when I only buy stuff that's on the convenience store shelf. Ok, I figure, they just didn't split it up (since if you don't pay at the pump you can pay inside).

But curiously, many (not sure if all?) other 7-11s (at least in the US) without gas stations (and that's most of them!) also post as fuel, not groceries.

(In my case, I don't have a Freedom card yet, but have to date always had cards which give me the same extra on both gas and groceries, so to date I've not been affected by the miscategorization of one as the other, but just wanted to point this out to those of you who are.)

I'm not sure about other (non 7-11) brand convenience stores...