Check.torproject.org message is ambiguous to rational non-technical user.
Showing an intelligent but non-technical user how to use Tor recently, I decided to direct them to the TorProject.org page and watch over their shoulder as they worked their way through it. Upon encountering the 'check.torproject.org' message "Congratulations, Your browser is configured to use Tor!" they then used the existing Safari browser they had open.
Fix: Change check.torproject.org message to "Congratulations, This browser is configured to use Tor!"