how do I notify members inside of wpforo of violations without having to send emails?
You have two ways:
1. Public way: to use the Admin Note Box. This displays a notification box on the top of the forum. You can write the notification in Dashboard > Forums > Tools > Misc Tab.
2. Private way: wpForo Private Messages addon. But it doesn't support bulk messaging yet. It only allows you to add users one by one in a conversation or send direct PMs. The bulk messaging to all users of certain usergroup will be added soon.