I also notice that one of the instructors of the early AM classes I go to absolutely does no modifications. She also is a bit more of a drill instructor than necessary; I don't like her barking in my ear (I'd like to have her meet my son, who really is a sergeant). I rarely go to her class anymore, but for me, it was OK, since I knew how to modify in the beginning. What's bad, is that if a new person comes to this class, they don't return. The thing is, I was already fit when I started this, I am a certified (though lapsed) fitness instructor, and I know what hurts me. Yet, I still felt like I was going to faint for the first few weeks. If I felt like this, no wonder others don't return.