Sounds easy, right? Not easy enough, as App Store rejection email told:
We’ve begun the review of ChatPoints for iPad but unfortunately we are unable to complete the review because we don't have a demo account to fully access all features.Lesson learned: even when your application has guest account and free registration, it is best to provide ready-made username for review. Never thought about that, because it would be too easy to customize service for certain pre-defined usernames...
You can provide demo account information, including passwords, in iTunes Connect <http://itunesconnect.apple.com/>. Under "Manage Applications," select your app name, ChatPoints for iPad, click on "Edit Information," then scroll to the "Review Notes" section and add the demo account details.
Really strange, but what can you do: Steve is right. End of discussion.