It would be great to add an option, so that the footer output )or any output really) is only shown to users of role admin. Or even restrict it to a user id!?! Or any user role...
I put some "ifs" in the code to just show it to admins, but I do not know how to add an option in on the admin side. Sorry, I'm not a coder, but can manage some if and stuff like that.
I just thought that would make your plugin even better.