Might pose a security concern, I mean there are protocols to adhere to regarding data protection with contact information and phone numbers... I'd wager that it's possible but a legal grey area.
I disagree that it is needed though, AppGameKit is for games and apps that can be created without deep knowledge of the devices - if someone needs to write an app that accesses this information, then I don't think AppGameKit is the platform for them. AppGameKit is a primarily for games, and I wouldn't trust a game that even wanted to access this stuff, in fact I'd uninstall it straight away.