Did a little digging on what the default USB mode "Samsung Kies" meant, and found it refers to Windows software Samsung makes to do media syncing. Trying to download it in the US leads to the message "In many countries, Samsung Apps is available for use on a PC. We aim to provide you with these services in the near future."

So they shipped a US only phone set to a USB mode that only works with software not available in the US. Clever.