Profile fields displayed twice on event registration pages

On the Drupal user registration page, Civicrm correctly merges duplicate fields between multiple profiles, so that the user isn't forced to enter the same info twice on the same page.
This unfortunately doesn't happen on event registration pages: if you have a "subscriptions" profile, for example, that collects the person's first and last name, these fields will show up a second time on the page (but the "email" field will be merged. +1 for that)