That's not a problem in Ren-X anyways. Unreal has had the ability to auto-download required maps and packages for years (at least since UT2K4). I think that this is definitely a case where it is up to server admins or moderators to enforce the policy, not something that should be an official feature.
Like Killa said, if they really really want the ability to have the mod itself enforce it, they should write a mutator.