I do not know if it is done manually or automatically, but I just want to prove a point that if DT member has been inactive for so long on this forum, there is possibility that the member will later be removed from the system. The link you even posted up there showed how easy someone can be removed from DT1 and if we think about it very well, also we can see how it can later lead to someone being removed from DT2 if all memebers that added the person are no more active and removed from DT1.