The chatroom module now has a feature to allow private "chats with staff" that are initiated via a button. Users who are not logged in get a disabled form button and some text that suggests they login with a link to login.

The css in prosper currently shows the disabled form button as a clickable element and it's not visually distinct from the style the button gets when enabled so neither the hover nor the inactive appearance of the button let a user know that it's disabled.