The address ban was from earlier this year, July, when i was flipping sets on Amazon. The volume was 7-8 orders on 3 accounts a day. With orders under 300-400$. Relatively minimal, considering two years ago I placed orders for 600 Iron Golems, 120 B Wings, 600 Sh*tter Robots, etc. I suspect my accounts were flagged from high volume last Christmas. Target has a fraud team according to customer service rep's i spoke to on the phone, who research and determine reseller activity.
It's pretty hard to avoid being spotted if you are a mid sized reseller. Imagine the number of people who buy over 5000$ of Lego from Target, 10K from Target, 20k? Run a query and you can see the top 100 people who ordered Lego from Target.
Target has more aggressively filtered "fraudulent addresses" as well. I'd open multiple accounts with variant addresses. Sometime in the summer Target data corrected all my variants to the USPS standard address (probably another reason I was flagged).
This spring I'm going to setup a more robust method for buyer account protection to maintain longevity in this business. Companies are going to continue to become more and more strict. They will begin to get smarter as well. With the improvements in capturing data and data processing, fraud or unwanted buyers are very easy to spot.