i have a student that doesn't trust the techniques and wants to go harder to make sure they work. i tell students to go easy on each other. lots of times injured students don't come back i don't believe you need to get injured to learn martial arts. when the student questions the technique its a little insulting to the instructor and everyone that has passed the technique on. in my dojo its training if you want to test your skills find a tournament or cage. ever had a student that didn't trust or believe in the techniques you were showing them? how can you make them believers without hurting them?