title: Downside to always using auth_type="rerequest" in Facebook login button (for required permissions)?
body: <p>I've got a Facebook login implementation (for a website, using the javascript API) for which I want the "email" permission to be required.  When the user first logs in, they may deny this permission - which is easy enough to detect by a subsequent look at the /me/permissions endpoint.  If I do find they've denied it, I don't continue with the login.  So far so good.</p>
  
  <p>Then during subsequent logins, to make sure they get <em>re-prompted</em> for that permission, I include auth_type="rerequest" in my login buttons (which may be rendered via either xfbml or a link with onclick=FB.login(...)).</p>
  
  <p>While this appears to be working, my question is: if I always want the permission to be required, <strong>is there any disadvantage to ALWAYS including auth_type="rerequest" in my login buttons?</strong>  I don't see anything to the contrary in the <a href="https://developers.facebook.com/docs/facebook-login/login-flow-for-web/v2.2" rel="noreferrer">documentation</a>, and it <em>appears</em> not to have any adverse affect on new users or users who've not denied the permission (i.e. it only changes the login flow - by re-prompting if the user has already rejected something.  Which is the behavior I want).</p>
  
  <p>Good practice seems to dictate that I should only include this when I actually know there's something I want to re-prompt, but for the sake of this question, I'd like to know if there are any pitfalls to just always including it.</p>