Expect a knock
My experiences at Japanese inns have all been very pleasant. However, to a certain extent, you have to remember the close quarters you are in. You will be getting somewhat familiar with the owners and employees of the inn as you will pass them by on the way to the bath, dinner, restroom, etc.
Also, one thing which surprised me, was when I was getting settled in my room, there was a knock on the door. An innkeeper then asked me what I wanted for dinner, and when I was planning on taking my bath. I was a bit surprised, as my experiences in other hotels have been completely isolated from any staff interaction. However, just remember that although a ryokan may seem very close and personal at times, it is all very hospitable.