Now the Notre Dame mark is interesting because the interlocking N and D was first used by the University North Dakota. Notre Dame used it second but they were not in overlapping markets so that was allowable. This was back before people were selling merchandise all across the country like they do now. Notre Dame obtained the federal registration for the logo, though, and once you do that, the law presumes that you are using the mark nationwide even if you are not. You get credit nationwide in terms of stopping other people from using the mark. But if there is a senior user, a user of the mark who was there first, then they get to retain the use of their mark in their original marketplace. So theoretically you are not allowed to sell a Notre Dame ND shirt in North Dakota.