When a student comes to the mat, there’s an implied contract they make with you as teacher. Staying safe, honoring one’s self, and practicing ahimsa (non-harming) is of primary importance.
As teachers, however, we cannot be wholly responsible for our students’ safety. We need to teach them to take responsibility for themselves and to build self-awareness. This may mean learning and respecting their limitations, learning to self-adjust, and practicing with less ego and more love for their wellbeing.
You will find yourself saying to your students the phrases “honor your body” and “if appropriate, you might try this option.” Please take time to explain what you actually mean by saying this as it will not be self-evident for most people.