I'm going to get on to my students for forgetting their music
Why are you going to give them a hard time for something so little?
There's a good reason and specific examples of why even one lesson can be important for them
I guess that this is just a part of life. It is normal to expect them to be prepared for their class. My music teacher was the same way in school.
See, so there is nothing wrong with me being this strict with them.
I guess not then. I think that you should expect them to come to class prepared, but try not to be too hard on them if they do not live up to your expectation.