Indeed topic positions must not be reused unless you also reset the
subscribers' registrations with 'QUIET SET listname TOPICS=-topicname FOR
*@*'. On the other hand, in the case of a short-lived "task force" style
topic, one can reasonably expect subscribers to understand that topics
are going to have to be recycled and that they may end up being
subscribed to a new "task force" discussion if the list owner forgot to
reset the subscriptions, in which case they should just disable that
topic (they will already know the syntax since they had to use the
command to subscribe to the recycled topic in the first place).
Eric