Suspicious Buyer Message from eBay

[cheechwizard]

I recently received this note from eBay (almost 48 hours after the sell):

"Suspicious buyer for item: ##########,

Hello cheechwizard,

We had to cancel bids for the buyer, XXXXXXXXXXX, because they aren't registered on eBay:"

I am glad to have Big Brother eBay watching out for me, but the user XXXXXXXXX(560) had 560 feedback references, what does eBay mean by "They aren't registered on eBay"...

Is this a fraudulent account set up as a ruse by a hacker? Can someone really penetrate eBay's defenses so deeply?

Can someone be actively purchasing and making offers with a non-registerd account?

Fortunately, I had not shipped the item yet, but the message went on to say something about "Contacting the Carrier" to retrieve the package  if it was not too late...

Was there anyway for me to know the seemingly valid account was non-registered?

Does this mean I need to hold all "expensive" packages for a few days to make sure I'm not at risk for a "Non-Registered" account?

So many questions, so few answers!

Thanks,

-Vaughn