I am currently working on deploying a large number (500+) of MacBooks out to users who will own the devices and sign in with their own personal Apple IDs.
Unfortunately whilst building the image we pushed, we logged into the app store and updated some applications, resulting in the iLife/iWork applications on that image being associated with the account used. Signing out and signing back in to the App Store after deleting the apps results in the price tag coming up to buy, instead of the "accept" option.
I've wiped one of the machines and put on a fresh sierra, and can confirm that the "accept" option comes up on the same machine with a fresh install.
Based on this information, I presume that the app store at some point sets a variable in a plist or creates a file indicating that this has been claimed on this device already. I'd imagine it reports the serial to Apple as well to stop abuse, however these machines serials have not been sent to Apple, they've just got some form of local flag due to the image.
Can anyone point me in the direction of the change made so that I can revert on all of these (now imaged) devices? Then users will be able to sign in and "accept" a license of iWork/iLife themselves.
I've found this article where the author discusses the method Apple uses to find adoption eligibility:
I've also found a Google Discussion post with similar information:
It appears the file on my test machine (which hasn't completed adoption and has our image on it has filled a plist with a valid "eligibilityRead" and list of all the apps, however they're still showing up with their prices in the actual app store.