Your reply to me says your reading comprehension is subpar.
On Xbox One, all your content is available in the cloud for access anytime, anywhere -- by you or by anyone you give you access to your gaming library. When you buy a game via retail on a disc, or if you buy it digitally via Xbox LIVE, it becomes available, instantly, in the cloud.
The only "account detail" necessary is for me to know someone's gamertag, and presumably that gamertag is already a part of my friend's list. Once I've setup my "Faimly" by adding gamertags from my friends list on Xbox LIVE, then Xbox LIVE knows who I've given access to my games. I may do this on my console, but Xbox LIVE has all the details.
Yes, anyone who is in my "family" accessing a game in my library, will need to be online and signed in with the gamertag (account) that's in my "family" list. This is all logical.
But as it stands, right now, if I'm not logged in, or some devastating act of nature wipes out my home and console, then anyone who I previously setup in my family list will still be in my family list and they will have access to my content.
Your console would have to be always online, even when playing single player using the family share technique. 24 hour check in is not sufficient. Otherwise, you would be able to do an online check in, disconnect from your network, and then start playing a "family shared game" off-line. How would they know of a conflict (when someone else tries to play) then?