At DeviantArt we want to have a default project if one isn't entered, so tasks filed with no project don't get lost. I added a herald rule for Maniphest with condition "Project does not exist" to add a project, but that rule seems to always match for new tasks. For example, see "Maniphest Task Test":

https://secure.phabricator.com/herald/transcript/45686/

Though it was created with a project, it was still flagged blue.