Yes, one should reasonably expect this but, as some of you know, I am not normal. lol I often explicitly request to be ignored during sessions. I'm self-conscious and don't like to be watched while I'm worshiping a guy's body, feet, ass, cock.. what ever. It plays into that dom/sub scene I so enjoy. So I always let him know that he is totally welcome to play on his phone, close his eyes, watch tv, etc. As long as his attention is not on me and what I'm doing... he could fall asleep for the whole session for all I care.
But I'm kind of odd, paying men to ignore me. I know this.
I also eat peanut butter on my hamburgers.