david,
It's against eBay policy to speak of the NARU'd, so I'll have to answer you in vague generalities.
Suppose I had three identities; pasnat for posting, natpas for buying, and tansap for selling. tansap has done a lot of selling, and eventually becomes a Power Seller, then a PSOTM. Cool.
But someone decides to check the feedback on tansap. And they see something a little funny. Some of my earliest FB is from a buyer named pasnat. Hmmm. They then track down my ID history and notice that I've got a lot of FB from eBayers I really shouldn't be too intimate with.
If someone were to point out that pasnat and natpas have done a lot of business with tansap, I could find myself in hot water. After all, as your mother always told you, it's not nice to play with yourself.
Of course, I only have the one ID, pasnat, so this is all theoretical and doesn't pertain to anything in particular.
Now to see if Sally is still pegged to the bottom.