For one thing, it returns far too many "false positives", meaning too many people have identical fingerprints, even though they are different users. This will always happen occasionally with fingerprinting, but it should be very rare. With this plugin, every time I would ban one fingerprint, as many as 4 or 5 innocent people are also banned. This makes the plugin basically useless.
Also, if you ban someone and their fingerprint becomes banned, and then delete that banned user, all the innocent users will still remain banned because of their matching fingerprint. Now there is no way to un-ban these innocent users without going into your SQL database on your server and hunting down each entry for each user and manually removing it from your SQL database.
There is a tab which is supposed to show duplicated fingerprints, but as far as I can tell, it doesn't seem to work correctly, as it only ever shows two users, no matter how many matching hashes actually exist.
There is also an issue where a banned user can log back into their account from a different device, and the fingerprint id for that device will be added to their account, but it won't actually be banned, requiring you to identify this user, un-ban them, and then re-ban them AGAIN in order to get that fingerprint id to be banned as well.
There are the beginnings of a good plugin here, but I recommend staying away from this one until it's been fixed. The high rate of false-positive duplicate fingerprints especially, makes this plugin mostly unusable right now.
