Well that's kinda the approach we have now. Most authors didn't reply because they simply have left the community or don't use their old emails. Only a couple of people have actually denied our request to host. I think now that JKHub is well established and the last place to host JK mods, those people that denied might be a little more willing to host their stuff here. But it will always be a sketchy topic. We make it easy for people to request that a file is taken down, right on the file page. You don't even need an account to request that, just an email.