1. What are Building "Schedulers" (as it's called in the calender system) able to schedule without any additional rights?
They are not
able to "schedule" any events or reserve any LDS Facility for a meeting. They are
able to create (a better term than "schedule") Restrictions, including "Blocked - Location Unavailable
" (i.e., not assigned to a unit). But your point is valid, "Building scheduler" heretofore was the wrong term. It should have been "Building Admin".
2. What is the proper term for Restriction, sub-category: blocked?
It's still a restriction and just says that no events can be scheduled at all by any unit
in the specified facility at the specified time. I did not understand before that this was the workaround many building admins have been using to "schedule" "events". But I can see how a blocked restriction could be considered to be equivalent to an event with an LDS Facility reserved (the building is unavailable to anyone else to schedule), but that is actually only by coincidence. They still are not the same thing.
I believe that the blocked restriction type was originally intended to close the building off during events such as General Conference, Family Home Evening, etc. But using it as an event scheduler mechanism is more a misuse of the feature and does not communicate to the user what actually is happening. That restriction type should actually probably be removed also to further cut down on confusion.