I heard home versions were all non-blockable, but the enterprise versions you could.
Most companies won't go anywhere fucking near Windows 10 unless they can test in-house with their software before pushing it out to the users machines.
Personally, I'm hoping that shit is the first thing hacked so you can block updates.
What will probably happen is they'll fat finger a update, trash a tens of thousands, or more people's computers. The publicity shit storm will force them to allow blocking of updates.
I personally always wait a couple days before updating.