Yeah, not all challenges come from unqualified individuals. What would you do if somone comes in the door who can kick your **** like a young Emin Boztepe did to William Cheung? Well, at my age I'm not asking for challenges, nor taking them. For me, MA is for fitness, for fun and for saving my backside if there is no other way out.
Nearly 30 years ago, I had just started teaching my first class of my own at my sifu's request. I really wasn't ready, but I did it to support my instructor. Well, a guy and his friend walked in the door and wanted to "check me out". He was young, cocky, and it was clear what he meant. He was also bigger, stronger, and more experienced than I. I knew this last part for a fact since he had been my senior and the assistant instructor at our school before we had a big split. And, I had never been able to beat him in sparring then... not by a long shot.
So, I invited him onto the floor, introduced him as my old si-hing (senior) and invited him and his friend to do a demo for us. After a thoughtful pause, he obliged, and it was a pretty interesting class. After he left, my students admired his ability but were a bit put off by his attitude. So I didn't lose any students that night.
And the other guy didn't lose any face either. In fact he went on to promote his own system of combat. I saw that he was on the cover of Black Belt again last year. He also recently directed the fight scenes in the new Sherlock Holmes movie. Hey... I almost got beat up by a famous guy! Pretty cool, eh?