Who owns “Who Dat?”S ome T-shirt makers are asking that question after they were hit with cease-and-desist letters from the NFL demanding that they stop selling shirts with the traditional cheer of New Orleans Saints fans. In a similar case, bookstores around the University of Wisconsin sold “Bucky Badger” T-shirts royalty-free for years _ until the university trademarked the mascot itself in the late 1980s and won its case in court.