First and foremost, I know this would be an absolutely huge undertaking.
A tag search for chartags:>0 copytags:0 shows that there are quite a few characters being tagged without their copyrights (some being big copyright series, such as touhou and vocaloid.) It's a simple mistake to make--I've done it a few times myself--but ultimately one that a lot of people are missing.
I won't ask how possible, because I know it technically can be done. Instead, how willing would our moderators be to go through the chartags and set up implications to their respective copytags, or even just hitting popular copytags to reduce the frequency of offenses? For example, all touhou characters implying touhou, all vocaloids implying vocaloid, all artist-proprietary non-franchise characters implying original, etc.
In the meantime I'm slowly whittling down the posts under chartags:>0 copytags:0.