As an example:
Tre Turner has a year left, decides he is transferring and wants to go to UVa (I know, I know... who wants to go to UVa, but this is a hypothetical). But, he still has to finish up classes in Blacksburg to graduate and be immediately eligible.
Would you want it out there in the public that you are transferring to the hated in-state rival while you are still attending class in Blacksburg? Or, would you rather have people think you are seriously leaning to, oh, say, Northwestern or somebody that would not be offensive to your soon-to-be former team?