title: Lock/disable/hide WordPress theme options until user has signed up for newsletter
body: <p>I am currently working on a custom theme's 'theme options' panel for a client that plans to distribute the theme for free after I am finished.</p>
  
  <p>The client would like the theme options panel hidden/locked until the user has signed up for a newsletter. I have never done this before and was wondering if anybody has come across a tutorial or can point me in the right direction.</p>
  
  <p>I've tried 'Googling' this topic for the past hour, but I haven't found anything useful. </p>
  
  <p>Thanks!</p>