I failed to find text that would define what could be appropriate matter
for a consensus call and what could not.
there are no rules on that question - in my opinion, anything in front
of a WG is fair game for a consensus call
For example, it is common practice to call for consensus on IDs or on
what to do with an ID. In a meeting, it is common practice to call for
consensus on a slide being presented on the screen or on an agenda item.
I've seen all of the above and think that is OK
the point I tried to make in my posting was that I think there
needs to be consensus to change something that has already been
adopted (more so if it was adopted a while back), and that its not
proper for a lack of consensus to keep as a consensus or mandate
to remove - i.e. there should be a barrier to capricious changes of
published IETF specifications
Scott