Well, 5th kyu 'instructor' is not good. Even beginner should have such common sense.
Perhaps...Perhaps Not...What if the 5th Kyu has a Sandan in Judo and a Godan in Karate...or experiance in Wu Shu or Gung Fu...
Heck we get students like that more often than not and everyone of them has a little common sense too...
One of things I love at seminars is watching "Aiki-Gods" (usually freshly minted Sandans) get knocked on their asses by "5th Kyu's" because the "beginner in Aikido" does not do Ukemi very well heh heh heh
Another old Himalayan saying... Those judging a book by it's cover... or a student by the color of his belt... May end up waking up looking into bright florescent lights.