I think the method of teaching, as well as the personality of the teacher, has everything to do on what the student becomes later in his practice. There's a saying in the military, there are no crews, only bad leaders. What you teach in your class, come back at you when the students get creative and are ready to make their own decitions. Most commonly the student follows his teacher's foot steps, and adds thoughts of his own to the teachings you taught him.
If you teach bad, the thoughts of your students can become corrupt your influence. I've seen in action and it breaks my heart everytime.
Aikido is also a reflection of life. What we teach in the dojo, reflects to the outside world. O-Sensei used to say that dojo is a place to practice life. That tells us that as well as good or bad teachings are reflected.
Although the students might be adults, we might as well be teaching children. From day one, they will absorb what you teach (just like a child from his mother and father).
At least this is what I think.