Facebook Email Extended Permissions Default Choice

I'm using the Facebook Javascript API to request extended permissions for "email". It works and the user can choose between real and proxied e开发者_如何学Pythonmail.

In my application, the default choice is the proxied email adress. I thought that was the default way for privacy reasons, but now my manager has seen this site: http://www.tripadvisor.com/ in which the default selection is the real email address instead of the proxied one and requested we implement the same.

What determines the default choice ? facebook, settings ? I haven't found anything official about this.

This is the code I'm using

FB.login(function(response) {
      // do some stuff
}, { perms: 'email' });

Thanks !

Facebook decides it. For newer and smaller apps the default seems to be proxied, but the official criteria are not public.