We have all wasted time tracking and correcting dubious profiles, branches & trees. The time for a clear strategy such as this project is advocating, is long overdue.
At the moment I have no suggestions vis a vis the descriptive terms to be used. However, whatever term(s) we decide to use, we must find a way to mark them in a way that all levels of user realise they are dubious.
My personal favoured solution is to colour each branch-line that joins profiles containing content of dubious historical value a bright red. It probably follows that each profile that relies on a dubious source so that inadvertent merges or changes to relations or data can occur without the cooperation of a curator or, perhaps better, that. any requested changes are submitted to a project designed as a catch-all repository for dubious sources?
I spend a lot of my personal research time using the feature in History Link that identifies Pending Merges and Parental Conflicts. Quite a few trees reach 25+ generations and I found it hit-and-miss picking our those with these conflicts that needed attention so I suggested to the developers that they highlight the profiles in red - if you take a look you will see what a difference it makes. I am now able to easily spot each one and correct any anomalies.
We need a similar device to ensure that ALL users can clearly recognise that a profile/branch should not be used or relied upon without advice. I feel that Colour-marking has the potential to satisfy the many different views on whether trees from sources such as popular fiction, saga, legends and religious references should be part of Geni.