George, you have brought to mind something that happened many many years ago when I was a young no rank.
The very first time I saw Saotomi sensei I was alone in an aikido club office in a school gymnasium when sensei appeared in full mountain man garb. Not wanting to get in his way I mumbled something and left him so he could have some privacy. A few minutes later after bowing in sensei gave a pointed lecture on how greeting another person, matching their intensity and presence was the entire basis of the uke nage relationship and budo itself.
Now I'm sure no one understood why sensei decided to address this topic because no one else had been present when he arrived, but I knew exactly what he was talking about and have remembered it all these years later.
So sometimes there is an audience of one. Or perhaps, it is always an audience of one.
Once, I began speaking with Saotome Shihan. I didn't bow because I had a cigarette in my hand. I hope to this day that he did not take it as disrespect since that's exactly what I wanted to avoid. I said, "Hello, Sensei," partly because it's more formal, and partly because I didn't want him to mistake "Hi" for "Hai." What's the general Japanese rule on this? Is it okay to bow with cigarette or anything else in hand? Fortunately, he didn't get into a lecture on the subject, but these East-West differences can be confusing to me. I suppose I just went with my heart by not bowing.