The Xbox One may not have online check-ins any more, but Forza 5 will require players to download a day-one content update before being able to play even the singleplayer portion. Effectively, the full game isn't actually on the disc.
“So when you first boot up the game, we’re going to ask you to log in,” Turn 10 boss Dan Greenwalt told IGN, “and when you log in you’re going to get the Drivatars and you’re also going to get a whole bunch of content: tracks and cars. Our production schedule is such that we are putting them in as late as possible and that means making them free as downloadable content on Day One.
“That is required content to play the game. We basically have designed the game to work with all that content no matter how late is coming in, in order to make the biggest game possible.”
Before you start raging, it's worth taking a step back and thinking about this. The update will be free, naturally, and probably won't affect the vast majority of players who'll already be automatically connected to the internet and Xbox Live (and already automatically connect every time they switch on their Xbox 360).
On the other hand, we like to play games without having to fanny about first. Thoughts?