Only a handful of my friends have actually tried one of my sessions in the 25 years I have been teaching martial arts. Now to be honest I never push it with them as that’s just how I am. The reasons for people choosing not to do a martial art are varied but one thing that keeps coming up is the fighting and striking each other. Most people do not want to hit another person or be hit themselves.
Within intelligent training, you should find it to be controlled, progressive and mutual thus providing a solid safety element to the training. To explain this, think of each exercise having a flaw. The flaws are numerous but one of the common ones is distance. With double stick drills for example distance is used so that the striking is done stick to stick rather than stick to hand or arm. The purpose of this drill is coordination, accuracy, timing and speed not defanging (disarming) your training partner.
All that being said, I have been smacked on the knuckles many times because mistakes happen and we are human. If your system and coaches are good, serious injury should be few and far between.