I think that avatar tags should have the letters colored by a simple system selectable through the profile or menu. This would be equivalent to "status" in YM or Skype.
Red: I am not interested in rl contact.
Yellow: I am not interested in immediate rl contact.
Green: I am interested in rl contact immediately.
Orange: I am interested in cam/voice rl contact immediately.
The status would pop up as soon as you opened an IM to them, so that you would know even before IMing them what their status is.
Failure to observe codes would be ToS violation. So "do you have cam?" to someone who is tag letter red, would be considered "griefing".