First, thanks for a great tool!
Given the frequency with which people change
their email addresses, I was surprised to not
notice any hints on how to do that
from the user's admin screen, e.g.
I see in the wishlist (http://www.list.org/todo.html)
that this is a goal. But until it happens, I suggest
just telling people on the admin screen itself that
'you need to unsubscribe and resubscribe under the
so they know that you know its a problem and they
don't have to search all around looking for how
to do it.