title: Can app be rejected if the user needs to log in?
body: <p>Quoting from the <a href="https://developer.apple.com/app-store/review/guidelines/" rel="nofollow">App Store Review Guidelines</a>:</p>
  
  <blockquote>
    <p>17.2 Apps that require users to share personal information, such as email address and date of birth, in order to function will be rejected.</p>
  </blockquote>
  
  <p>My app let the user logs in via email and password (so far it'd get rejected), but it also provides one-click login with Facebook. If the user logs in with Facebook, he is able to deactivate the <code>email</code> permission thus letting him in without providing an email address at all. Is this acceptable as per App Store point of view?</p>
  
  <p>The reason I'm asking is because App Store Review Guidelines are very subjective. It doesn't specifically says this way I described could get rejected, but I wouldn't be surprised if they did.</p>