I want to create a mini-plugin which, among other things, creates a category for each new user created. There's an action hook for when new users register (wp-register.php), but for my particular application, I don't want new users registering. I want the category to be created automatically, when a new user is created through the Admin panel, and there doesn't seem to be a hook for this.
Any suggestions? I could always put the hook in there myself, but then it would be wiped out, and my plugin would be broken, the instant the WordPress installation was upgraded. This wouldn't be a big deal, except that I'm making this website for someone else, and they don't want to have to keep track of these things when the upgrade WP.