You would need to make a plugin to listen for a socket event, and in the widget js send the needed data to verify the request server-side. After adjusting the reputation and sending the new rep back, you probably want to make a db key to record the last action taken, such as how core uses pid:x:upvote
Auto-ban for low reputation was an option in the ACP, am I wrong? Now I can't find it (v0.7.2). Also there is no banUserForLowReputation() in the code. The settings had meta.config['autoban:downvote'] and meta.config['autoban:downvote:threshold'] properties, now I can't find them.
Any good reason to remove this functionality? Just curious.