I agree. You are either a fan or not. If someone can get out of the habit of going to the games (as another poster stated) I have to wonder how big a fan they were in the first place.
You can call them whatever you want---fans, non-fans, consumers, alumni, pond-scum, casual sports enthusiasts---but the fact remains: If they quit coming and quit donating, you're better off figuring out a way to get them back rather than just say, "Well, they aren't REAL fans anyway."
A TERRIBLY short-sighted notion, that is.
Those people who aren't "REAL" fans are DESPERATELY needed, because they make our dollars (mine, yours AND theirs) go a LOT farther. If we don't win them back and keep them on board, we're ALL just pi$$ing in the wind, singing "We are the sons of Marshall . . . but YOU'RE not!"