relay it to the @code{nodeA} also, that will silently remove it when
tossing, because it was already seen.
-@strong{TODO}: we must not relay packet to the node also presenting as
-the sender of the area's message. Obviously it has seen it.
-
@item
When @code{nodeC} sends message to the area, then @code{nodeA} will
receive it twice from @code{nodeB} and @code{nodeD}, ignoring one of