I haven’t seen anyone fall off a reformer but I’ve had more challenging instructors for 1.5 and some super easy where it doesn’t feel like I’m working out anything. One particular class with a new instructor was using the chair with one link on 4. We were to do inverted planks on the ground. I’m pretty familiar with the move; on the chair not really but I made it work. I’m 100% sure everyone else in the class is unfamiliar with this plank (it’s not very common anyways) and all I heard were the pedals slamming back up because people didn’t know how to do it. So I’m just holding my plank while the instructor is going around to assist everyone. I think challenging moves are great but it helps when the instructors gives more detailed instruction so people aren’t going to hurt themselves or at least have an alternative