Talk of IP-based restriction has been around ever since Video Marketplace went online. Last time there were talks of restricting marketplace contents, specificially video contents to only IPs that belongs to each country. That did not happen.

What did happen was they restricted MS Points purchase via credit card based on IP (if I remember correctly). So if you have US account and you're staying in Malaysia/Singapore, and say want to purchase MS Points, the only way to do it is to buy Asian MS Points card. A US points card won't work.