When I traveled with the cat, I booked seats as far removed for anyone else as possible. Then, on the day I left, I doublechecked the seat chart for my flight. I saw that they had, for some reason known only to God and Delta, assigned all the seats around me, leaving a huge number of seats open elsewhere on the plane. Go figure. So, when I got to the gate, pretty early, I asked if I could change my seat assignment to one with no people around me. Now, I had the cat carrier in my hand, so it was pretty obvious that I had an animal, and I would have thought it would be noted someplace for the gate attendents to see. But, the gate personnel asked me if I had a problem being seated near people, and if not, why would I want to change my seat. I had to explain that I was flying with a cat (already paid extra for and duly noted I would have thought) and had orignally chosen a seat near the rear of the plane with few passengers in order to decrease the chances of bothering anyone with the cat. Thought that made sense. But, they did move me to an area that had no one beside me or across the aisle from me, or behind me. There was an older couple in front of me, but I asked them if they had any 'cat' issues and they said no, so I figured I was good to go.
I would have hated that the cat would have impacted anyone on the plane and did my best to avoid that. Now, if someone had come along, with a severe allergy, I would have expected to get bumped.