In a system with many authorities, keeping communication straight is critical and difficult. The termination of memberships is the most problematic area of design. I have not yet implemented a termination warning, because I haven't been quite sure what the best policy's are. In almost ever case, I can think of counter policy for notifying someone about termination. However, I am sure that I want groups and memberships to terminate.
Groups fall out of usage.
There are already hundreds of groups and there need to be termination rules. The group management functions have been developed in the last 3 years, with the class list information being used for about 2 years. Throughout this period there have been 2 persons working on this and other projects. Each increase in function has broadened the amount of usage on campus.