In a word: bureaucracy.
Let's say my name is Mary Sue Balfour. Apparently when registering for grad school on some form my name got switched to "Mary Balfour Balfour." Now the registrar's office cannot be convinced that that is not my name. We have a go round every academic term where they say my tuition hasn't been paid, when it turns out that Mary Balfour Balfour's tuition hasn't been paid, but Mary Sue Balfour (who has the same ID number, birthday, address and phone number) has paid her tuition.
Every quarter, they request that I provide either A) a copy of the court document where I legally changed my name from Mary Balfour Balfour to Mary Sue Balfour or B) two pictures IDs; one with my "old name," Mary Balfour Balfour, and one with my "new name," Mary Sue Balfour. However since my name never was legally Mary Balfour Balfour, I can't provide any legal documentation that my name was changed to Mary Sue. Eventually some supervisor sighs and agrees to credit Mary Sue Balfour's tuition to Mary Balfour Balfour's tuition but I really need to fill out the legal paperwork.
Unfortunately this office releases the tax document that shows how much tuition I've paid during the year. This time I came armed with that and showed that all the information from the university's W-2 under the name "Mary Sue" was the same for "Mary Balfour." The supervisor visibly recoiled and said she couldn't look at anything with a social security number on it!
And no, it makes absolutely no difference to them that there is only one Balfour (much less a Mary Balfour) associated with the university and according to all the other systems, including payroll, HR and IT, her middle name is Sue, not Balfour.