I think this thread has been long overdue and the recommendations put forth here would resolve a lot of the barriers or shady areas to mod making. Especially the fact that a modder may not be able to be reached for his permission to use his work. A collective copyright notice would solve that for sure, where each who wishes to make his mod available to others can publicly state so, specifically in entirety of the mod or part thereof and give even further exposure to the mod created.

In particular with the read me files with mods and copyright notices it seems to be an issue of 'in part' or 'whole' mod property. This would be resolved too, without digging around in read me files for info or the method of acquiring permission. The collective copyright notice could be pointed out in such a file as reference, which would include all those who wish to disseminate their work in whole or part as pointed out in their post addition to the notice in relation to their specific works.

The other benefit would be that the creators are attributed in a more public way and their particular contribution; e.g. being a unit or as specific as liked. It would also act as a repository of skilled modders in a way, as per their specific skills enjoyed by the community.

Good idea hope it works!