If there were roots in the main drain or any rough spots, the rag could get caught and the toilet paper would clog it all the way.
Reminds me of a story. In my mid 20s/1995, my first house had a bath in the basement and a buddy from work lived with me and stayed down there. This bath was added in the 80s to this 1908 house. Anyways, things backed up through the floor drain in the basement...Raw, fresh sewage. We cleaned up a bit and I proceeded to snake the floor drain. As I did I was stirring up chunks and my buddy was getting angrier. He was giving me a pretty bad attitude about it all, like because it was my house, it was my fault. As things seemed to clear and as I pulled the snake from the drain, wads of paper towels were pulling out with the snake. I looked at him, he looked at me..."Sorry, man. I ran out of toilet paper..." He cleaned it up and I think he also bought the beers that night.