Often a Master is challenged for a test! This could be under the excuse that in order to learn from him a student want to be personally persuaded that the Master has superior abilities and therefore someone to admire and learn from.
In fighting sports for example or so called Sports Martial arts, Master should have had enough sparring experience at some point of their careers to reach their rank. Some that might not done well in sparring, but provided good administrative service, or good attendance were promoted as well! In a vague quest for improvement, a rank is always appreciated as recognition of persistence and advancement. People do get old, sick, lose their mobility, etc.
When a person is dead, although non existing he still retains his name after his death! Some people are always looking for easy challenges, and some people are always looking for all sorts of challenge.
Most people probably just heard too many senseless folk fables and nowadays watched too much television!
From the above extreme scenarios let's take a more feasible scenario, where someone comes to you and calls you for a friendly sparring.
Obviously, if someone provoked you and entered the hotzone aggressively, you would have had no choice but to use your skills for better or worse. The fact that someone is asking you to agree for a friendly sparring means that you either take his invitation for a dual or lose respect!
As a H2H professional, who is sure of himself you at times happen to stretch yourself beyond the possible element of surprise possible to stop in order to protect your students well being. Many times you hold off from inflicting a blow that will severely cripple a potential student in such stupid challenge.
Professional boxers and wrestlers now realize that in order for them to compete in MMA, they need to learn more! Its time to realize that in order to spar in self defense training, you need to learn more than ever. It is totally a more comprehensive approach then all the others and more specific.
Fighting Sports give great fitness and abilities from the fact that the simple moves of a match are stretched to hard training and fitness which are aimed at giving athletes the opportunity to experience the hard work and sense of victory achievement in a limited injury capacity!
So to simplify the point, lets say you are H2H Instructor, and someone asks you to do a friendly sparring. You can kick his balls before he finished talking and elbow his head and walk away!
In Pure Krav Maga, students learn to timely respond to a potential attack and deflect or counter attack almost at the same time in the priority of which is faster. That causes an immediate reversal of fortunes.
On occasion, a trusted student might come and attack you knowing that you will not hurt him bad with your counter, and try to attack you again... At times you might not think it is a good idea to hit him hard back. From a show point of view you can lose face! But if you did hit him hard and injured him, you have lost a student and got yourself a bad reputation!