I've read numerous accounts on other online forums where Amazon customers were banned and Amazon hunted down and systematically closed any other accounts the customer had previously as well as any new accounts they opened after being banned. The new accounts opened post-banning sometimes took a few days or week(s) before they caught it. And while I read of a very small number of account holders who were able to convince Amazon (a special team - as regular customer service reps cannot do anything) to reinstate their account, the vast majority reported that they ran into a brick wall with Amazon ignoring their requests and leaving the ban in place.
What it takes to get banned I don't know, but wish I did since it makes any Amazon customer aware of this phenomenon nervous about any return or request for credit, even legitimate. How often it happens I also doubt anyone outside of Amazon knows.
I would assume they use a combination of some or all of the following attributes to match accounts to a single identity:
Name
Address
E-Mail Address
Phone number
Credit Card number(s)
IP Address logging into account
The last one is quite powerful. You might change the spelling of your name or use a fake or family members name and email/phone plus use a different physical address (if you're lucky enough to have easy access to receiving shipments at a different address never before used on the old account - since if you ever ship to any address (or save a credit card or phone, etc.) ever associated with the old account, you will let Amazon catch you) and a brand-new never before used credit card. But your home and/or work IP address does not change too often. And you are more likely than not to login to your new Amazon account with an IP address you previously used to login to your old (banned) Amazon account. Of course while Amazon is well aware that some IP addresses are (legitimately) used by completely unrelated account holders (different employees at work, public computers, dynamic IPs, etc.), they likely use powerful algorithms to make an educated decision based upon the IP, name, address, frequency the old and new accounts used an IP (and whether other accounts previously used that IP) and other factors in determining whether they think it is the same, banned, customer.
Presumably if you use all of the following
*new name
*new address
*new e-mail address
*new phone number
*new credit card
*new IP address
and are extremely cautious to never (even mistakenly or absent-mindedly) enter or otherwise associate with your new account any name, shipping address, or credit card ever used with the old account --- and you are sure to never login to your new account from an IP used to login to the old account, you increase the likelihood Amazon won't get you.
