TransUnion has failed to remove an incorrect report of collection long after Experian and EquiFax have verified it incorrect and removed it. AFAIK, this is a violation of Federal law. They are not even reporting it as disputed in spite of several phone calls. They are also failing to report changes that the creditor claims to have sent and which the other two agencies have already updated.
That's background. Because of this, I have considered advising the "victim" (a relative denied credit due to this nonexistent collection) to lock TransUnion against inquiries. But before I go out on that limb, if he has a good score from the other two, but Trans cannot be queried, will that work against him?