The white card approach is similar to the user note on profile, except that the user note function is useless.
I understand that what your want is to do several things:
- alert staff of the issue with user
- have the same notification visible for staff on the users profile
- the user should not be aware of the notification.
I think your white card idea is brilliant. Though to properly notify staff, I think such white card notices should be posted to a staff thread. And IMHO optimally there should be 2 threads: one for worrisome members and one for rising members. The notices for worrisome members could be done with black cards and the notice about rising/positive member could be done with a white card.
I would very much like to have functionality like the above, because it would make my staffs life a lot easier.