The quotations say nothing of the sort. A vendor could provide a dual-boot device providing they have an Android bootloader signed with Microsoft's signing key, which is a service that Microsoft will be providing.
A more open question is whether any of the existing Linux vendors will be doing this. Fedora is willing to use Microsoft's signing service for x86 because users will be able to disable the feature or enrol their own keys. We're not willing to do that for ARM because users won't have that freedom and so wouldn't be able to replace components like the kernel.
>"A more open question is whether any of the existing Linux vendors will be doing this."
The Market Economics Fairy predicts that they will not given the limited number of people who are interested in dual booting a tablet and the diversity of device configurations likely to be manufactured.
Limited number? Quite a few enthusiasts will buy x86 tablets JUST for this purpose. Sure, enthusiasts, but enthusiasts also drive Linux to some extent.
The enthusiast market + the small business market for Linux is so small that no significant manufacturer builds Linux laptops for the consumer segment. The enthusiast Linux tablet market will probably be rather smaller.
edit: I'm sorry to see the child comment downvoted. I am under the impression that user key enrollment is disallowed, but I'm actually not seeing an mechanism by which Microsoft can prevent the signature of ARM based bootloaders.
That having been said, I don't completely understand ARM devices to know if it's plausible to sign an ARM bootloader with the MS key.
edit2: The person y'all downvoted is the guy who wrote the blogpost outlining the Fedora way of handling this issue: http://mjg59.dreamwidth.org/12368.html
So your understanding is that manufacturers will still be able to add their own "instant boot" capability for media playback or quick access to contacts, but will have to have the system image signed by Microsoft to do this?
A more open question is whether any of the existing Linux vendors will be doing this. Fedora is willing to use Microsoft's signing service for x86 because users will be able to disable the feature or enrol their own keys. We're not willing to do that for ARM because users won't have that freedom and so wouldn't be able to replace components like the kernel.