Re: Instructors of low rank
We could expand this discussion to include "Why did O-Sensei award several non-aikidoka verbal 10th dans?", "Why did he leave Saito Sensei custodianship of Iwama?" and others, and the answer would be the same: we don't know what the intention was.
O-Sensei is no longer here to answer our questions, but the sensei appointing the low rank as instructor for the day is.