Uniqueness of project title

[bemoody]

Nothing currently stops somebody from submitting (and if accepted by the editor, publishing) a new project with the same title as a previously published project, by the same authors or by somebody else.

Should there be a warning? An error?

[tompollard]

Should there be a warning? An error?

Either a warning to both the author and the editor, or an error. I can't really think of a good reason why it shouldn't simply be an error ("That title is taken: please pick another.").