Thank you for this idea.

In my opinion, sources are the single most important thing on a post.
You can always add new tags quickly (even if lack of tags makes posts hard to find later), but finding the source after a year can be a real bitch.

In addition to requiring a post URL like https://www.furaffinity.net/view/###
it would be nice if the direct image link were *also* required for some sites.

Like Tumblr.
When a Tumblr post gets deleted, the direct image link remains active.
So you can still upload the BVATS even if the post has been deleted.

It's the same for Deviantart.