Kickboxer101
Master Black Belt
Firstly, this guy is not willing to show up, so you've just changed your stance on him.
Secondly, there are people who show up to show off or to be able to brag about what they are doing. Those folks are not there to learn. They get a chance, but their attitude is detrimental to the learning of others and eventually presents a physical risk to others (because they often show off by over-doing a technique they don't understand). Before it reaches that point, it's the responsibility of the instructor to remove the problem.
Yep seen those type I had a friend who came to my club and sat out and watched a session then next day went round telling everyone he does kickboxing...and never turned up again but kept on saying he did it