It makes me incredibly sad to read these stories. I remember taking my open water class, and being VERY frustrated because I couldn't kneel without falling over. And you know what? In my entire subsequent diving career, all thousand plus dives of it, I have never encountered a situation on a dive where being able to kneel comfortably was necessary or desirable. Why do we frustrate students with trying to do something THEY DON'T NEED TO DO?
In my husband's classes, students neither kneel nor sit. They lie on their stomachs (which is generally pretty easy to do), rest on their fin tips, or float. It's amazing how easy those things are for students to do, compared with kneeling. And those positions are directly analogous to actually DIVING, and what divers do. If everyone learned this way, we'd have fewer frustrated novices, and fewer divers kneeling on the coral to reposition their masks.
Excuse my soapbox, but I feel very strongly about this.