The theory is that sometimes debts that you dispute (not yours of course or reporting incorrectly!) are harder to verify (again incorrectly verify) if your CRAs only list you current, correct name, and current, correct address. Many times this is an electronic process that just confirms there is a debt with your name (any version on your CRA) and an address on your CRA (again, ANY address). They are SUPPOSED to do more, but often dont. SO, if that old, inaccurate information is not there, they cannot then verify incorrect information.