I think reactions like that are a small case of low self esteem, as in, people who don't like to be "tricked" because they'll feel like fools. To some of these people, no matter how inviting we are as performers, they will never get over the idea that "This guy is about to trick me. I'm not stupid." I had a friend who was semi-aggressive about this. I would show him an effect and he would yell "Dude, I'm not f(riggin') stupid." And then grab my deck/props and try to "show me" how I did it, and when he couldn't, he would be quiet. Every single time! Of course, I slowly stopped performing for him. Some books on audience management are fantastic, but we have to accept that sometimes, we cannot change some people's views on our craft because of their personalities and "fixed" views. Just some people though.