Now that my XPS 8960 has arrived and been setup, I can confirm that it arrived with the WiFi adapter disabled, probably because the computer detected an Ethernet cable.
My soon-to-arrive XPS 8960 has both an Ethernet adapter and a 'killer' WiFi adapter. I plan to use an Ethernet cable.  I learned that the priority of network adapters is determined by their interface metric value. The adapter with the lowest IM value takes priority over others.  Does Dell ship XPS desktops with interface metric values set so that Ethernet (if present) takes priority? So I don't have to somehow 'disable' the WiFi adapter in order to use an Ethernet connection?
XPS 8960, Ethernet vs. WiFi when you have both?