If this is true, its really unfortunate. Local multiplayer is a lot of fun and limiting it to only two or three players is a bit of a disappointment. I’m hoping this is a software issue that will be fixed shortly.
Update: SchwarzTech noted on Twitter:
Hopefully a software limitation, but perhaps Apple assumes more iOS devices as extra controllers/remotes initially?
This is something I hadn’t considered, but sounds like a plausible reason for Apple to forgo support for more than two Bluetooth controllers at launch.