Why would a conference ask for a title page if the submitted paper has been submitted somewhere else? I am in the process of submitting a paper to a conference. In the submission page I read:


  Title Page (Mandatory if multiple submissions, submitted to a
  pre-print archive, or substantial overlap with prior publications)


Why would a conference ask for a title page if the submitted paper has been submitted somewhere else?
I'm hardly an expert on this topic, but I have coordinated the online content for professional conferences (as opposed to academic conferences), and based on how this requirement is worded...

I believe it implies that they ask for the title page so that any existing instance of the work online can easily be identified as your work specifically, and not any indication of plagiarism. I also would think it protects against an attendee later writing something that plagiarizes a paper which was presented at the conference, without proper attribution. 

I'm not sure if there's yet another layer, of how they would cite a paper they first heard about at a conference, in regard to the container within a container format of citations. But it could be yet another reason they would make such a request, just to cover bases.