[solson]

I don't know exactly what sets the flag off, but it is something like IP address, cookies, hardware, or some combination.

I also got the impression from the way they described the multiple phone calls to Amazon CS that the decision was made by an algorithm or some bunkered third party security firm that CS could not contact.

I'll have to check with these folks and see if they are willing to do a blog post about it. The one that is still selling is justifiably afraid of what could happen to that business.