Whenever I've ordered a roast beef sandwich anywhere else, the meat is served cold. This has been echoed by acquaintances. You've had warm roast beef sandwiches in the south also? Mostly just curious!
I completely understand something being less prevalent in various areas. Certainly barbecue places are generally few and far between here in MA, NH & ME.
I've had both, but I prefer heated. I think it depends on the type of establishment. Also, whether it is being prepared fresh for you. Pre-packaged (or pre-sliced, but not universal) tends to be cold while fresh tends to be warm. Then there's toasted which obviously comes out hot.
I guess it could also depend on the definition of cold sandwich, which could be different region to region.
I completely understand something being less prevalent in various areas. Certainly barbecue places are generally few and far between here in MA, NH & ME.