Re: It's a conspiracy
"Trevor, a large number of users will not have Windows as a "free" upgrade, so they're definitely going to be bricked if they get auto-updated.
Anyone else who updates without backing up first runs a fairly high risk of losing data. That applies to ANY update of ANY operating system. "
Don't disagree with you, for evidence we need to look no further back than the W8->8.1 update.
I had a client with a number of HP laptops that shipped with W8, but even a year after the release of 8.1 HP hadn't shipped 8.1 drivers and stated on their website these systems didn't support 8.1. This didn't stop MS via WUP attempting to update these systems...
And yes at the point WUP told the user it was updating to W8.1, it gave them a maximum of 4 hours to do whatever before it forceably went ahead with the update... Interestingly, MS didn't ask at this point whether the user had backed up their system prior to it going ahead with the update, so they must have been confident that they had minimised the risk of data loss directly caused by their action.
"Microsoft is NOT going to take that risk on everyone's behalf by upgrading them while they're asleep. Surely you don't think it will, do you?"
So in answer to your question, Microsoft will take a risk on everyone's behalf if it deems it acceptable.
However, the biggest risk (in my experience wrt to the loss of user data) isn't Microsoft, but the approach taken to recover the system. The on disk recovery tools tend to direct the user into doing a re-image without first giving the option of recovery, so a total loss of user data. If the user takes the bricked system to the professionals, the majority of these will simply reformat the HDD with a new install without first bothering to mount the disk under another OS and recover the user data...