NOT13 — Issue with pushing events

2. Publishers are allowed to push events for the types they have not offered using offer_change().
This can allow publishers to never advertise the event types they are offerring. For Example, as
a consumer it can not tell what are the event types that will be offered on the channel.

Can we require publishers to always call offer_change() on the new event types before pushing them to
the event channel? If this behavior breaks existing functionality, then how about having push_xxx()
check to see if the event type is offered, if not add it to the aggregate list?