I notice that other websites are reporting that MS has also said...
“Xbox One is designed to run in a low-powered, connected state. This means your system, games and apps are always current and ready to play—no more waiting for updates. While a persistent connection is not required, Xbox One is designed to verify if system, application or game updates are needed and to see if you have acquired new games, or resold, traded in, or given your game to a friend. Games that are designed to take advantage of the cloud may require a connection.”
“You can game offline for up to 24 hours on your primary console, or one hour if you are logged on to a separate console.
“With Xbox One you can game offline for up to 24 hours on your primary console, or one hour if you are logged on to a separate console accessing your library. Offline gaming is not possible after these prescribed times until you re-establish a connection, but you can still watch live TV and enjoy Blu-ray and DVD movies."
Microsoft added "because every Xbox One owner has a broadband connection, developers can create massive, persistent worlds that evolve even when you’re not playing."
This seems to make clear that you will be unable to play offline unless you connect to Xbox Live every 24 hours on your primary console.
I cnduo't bvleiee taht I culod aulaclty uesdtannrd waht I was rdnaieg. Unisg the icndeblire pweor of the hmuan mnid it dseno't mttaer the oderr the lterets in a wrod are, the olny irpoamtnt tihng is taht the frsit and lsat ltteer are in the rhgit pclae.