Bending over instead of squatting

I mentioned that a lot of people in my gym classes cheat heavily when they're doing their moves. These people, I hate to say, will not see much by way of results.

For example, instead of squatting, they will typically bend over a little bit. This requires a lot less effort, though their backs might feel a bit sore the next day. Our instructor routinely points out that they're cheating, but that doesn't stop them.

I'm also a little bit annoyed at this woman who joined our class, and who consistently moves with the wrong arms or feet. This is a problem when doing side kicks, since it means that she could wind up hitting someone. It could also be a problem if she were to move in the opposite direction as the rest of the class, darn it.