Windows certification is not necessarily the same as Windows licensing, and given the history, that is likely to remain the case.
The article conflates the two: "a document that regulates licensing (certification) (pg. 116): "
But Microsoft is clear: "The new Windows Hardware Certification Program (formerly known as the Windows Logo program) makes it easier to certify your hardware for Windows 8. Use the requirements to build and certify your Windows-compatible devices, systems, and filter drivers across all Windows platforms."
Considering that WOA will not be sold separately and how MS touts tight integration with hardware, I'd be willing to make a bet that consumers won't be able to buy an ARM device with WOA that can boot to Linux (without exploits).
"Partners will provide WOA PCs as integrated, end-to-end products that include hardware, firmware, and Windows on ARM software. Windows on ARM software will not be sold or distributed independent of a new WOA PC, just as you would expect from a consumer electronics device that relies on unique and integrated pairings of hardware and software"
No, upshot is that for ARM you can't get Windows at all (certified or not) if you allow other operating systems to boot.