Several times recently, in Baton Rouge in particular, I have ordered "macaroni and cheese" as a side dish. In each case I have been surprised to get what I would call "spaghetti and cheese." To my literal, Eastern US mind, that is a different dish. [Actually, sometimes it was a mixture of spaghetti and linguine.]
A number of months ago, we were at our favorite barbecue joint in New Orleans, Squeal (on Oak Street). It is walking distance from home, go there! We asked why they did not have M+C on the menu. The owner/co-owner said that they had not been able to develop a dish which would stand up to waiting and being served with the right consistency. [As a home consumer, mostly immediately, I had not thought about the heat-table issues.] By the way, the menu at Squeal rocks...and they sometimes have "bacon vodka." The latter is a real treat!
I got to thinking about the meaning of the word "macaroni." For me, macaroni refers to a hollow shape of extruded pasta which has a hollow interior. For the most part, it is "elbow macaroni" (i.e. with a slight bend) and could be extended to ziti, rigatoni, and other hollow shapes. Interestingly, Wikipedia seems to agree.
I have heard Italian-Americans in the northeast use the term "macaroni" to refer to all pasta as macaroni, but that has been rare. Now, I have made pasta (linguine, spaghetti, spaghettini, etc.) but all of those are noodles, not extruded.
It has been an interesting change. BTW, Italians have been in the New Orleans area almost as long as they have been in the Northeastern US.