I have run into a few. Years ago during a Jun Fan/JKD class my instructor paired me up with a visitor who was interested in JF/JKD. During a low side kick counter drill, I allowed my partner to work on the low side kick (Stop Kick) and he did a fair. I had no issue with him then, but when it came to my turn to work on obstructing his low side kick, he knew how I would move for the drill and kept lifting a (Good I have to admit) high TKD side over my obstruction. I said thats good but lets stick to the drill. Again and again he knew as long as I stuck to the drill, he had free shots on me. At one point one of the guys from our club said "Sir, Jimi's partner is not sticking to the given drill" seeing my disatifaction at the drill exchange. My Instructor told him to "Do the drill as instructed" As we continued the drill he was grinning at me like there was nothing I could do to stop him. It got under my skin, so the next exchange I reach my low side kick deep under his lead leg as he tried to plant the TKD side kick on me again & I took his support leg right out from under him bouncing him off the wall behind him onto the matt. Everyone stopped to look agasp. My Instructor insisted "What happened Jimi?!" I responded "Ask him sir" all the while my class mates were watching with looks on there faces like he should not have broken from the drill so much with Jimi. He explained "I was just trying to show my partner the function of a TKD side kick" My Instuctor was not happy with either of us. He countered "Jimi is quite familar with the TKD sdie kick, but that was not the drill I gave you. Jimi, What happened?!' I said "He kept breaking from the drill, so I went at it with a little umph and took his support leg. Then I allowed him to explain himself to you." My Instuctor called for a 10 min. break then telling this guy to be more respectfull to a training partner who has put his safety in your hands, the guy apologized & my Instructor took me aside. "I understand why you did that, he was out of line, but don't do that S***! again!" He demanded. This guy did not last long in our club, but I think he took more of a lesson from me than my Instructor. LOL. PEACE JIMI