At JKHub we require author's permission to be uploaded, and if it's granted, we move the file to a neutral account, and make sure the author's name is the biggest font and saying it's theirs. If someone can't reach the author at all, we allow it to be uploaded if it's been longer than 30 days since they attempted contact. And we have a link for the original author to contact us if they want it taken down. That's handled completely by us, no need to even tell the uploader because it's not even their file.
We do ask for proof of attempted contact with a timestamp, like from an email or PM or something. That way we can show the author an attempt was made.
We made that the new policy because we understand that a lot of JK modders simply moved on from the community completely, and probably will never return to upload their files. But if they knew FileFront was gone and JKHub was the main place for their mods to be downloaded, I'm pretty confident they'd be okay with it. And if not, we can take it down.
Obviously this is a grey area, especially around here, but we feel it's the best compromise we could reach.