There's a lot of models uploaded that are just re-uploads of other models available on the site, with the same hash. Sometimes by accident, sometimes maybe less accidental. Two different places for warnings would be helpful here. First a warning to the user while they're uploading, reminding them that this model they're uploading already exists on civitai (look it up by hash), and make sure this is really what they want to do. Secondly a warning on the duplicate model page advising everyone that this is a re-upload of another model (perhaps with a link to the copy that was first uploaded). The first warning helps cut down on legitimate mistakes, the second one helps prevent people from building a reputation off of someone else's work.