title: How to display a value where there is none in Django admin?
body: <p>Is there a Djangotastic way to display a default value for a field in the admin when there isn't a value? Like 'n/a', but not to save that to the database?</p>
  
  <p>When I set all the fields in the model below to readonly in the admin, the front-end display looks like the image at the bottom. It feels visually collapsed like it should have a value or a box or something. If there isn't an easy way to do what I am looking for, then is there another solution to make the front-end admin more clear for the user?</p>
  
  <pre><code>class Package(models.Model):
      packaging_format = models.CharField(max_length=40)
      package_delivery_pattern = models.CharField(max_length=30, blank=True)
      package_delivery_comments = models.CharField(max_length=250, blank=True)
      package_manifest_filename = models.CharField(max_length=50)
      package_description = models.CharField(max_length=250, blank=True)
      package_naming_pattern = models.CharField(max_length=50)
  </code></pre>
  
  <p><strong>Screenshot of fields as displayed in the admin:</strong>
  <img src="https://i.stack.imgur.com/AIP7J.png" alt="Screenshot of admin with readonly package fields"></p>