"He must of used marked cards..."
Now that reaction may happen before, during and after a show you must plan for it.
There is also no problem with someone having this reaction. It is understandable for a magician to be defensive to this. The worst thing for me is when someone thinks that I did something that I didn't and I want to correct them so they are not misinformed but they will not believe me unless I reveal how it is really done. To me when I see magic even before I started doing it myself it wasn't important how they did it. What was important is what they did, or at least what it looked like they did. When I could see through a trick it annoyed me. I did not want to see a trick, I wanted to see magic. Don't get me wrong I knew it was a trick but when I watch a movie I don't like things that reminds me it is just a film and it all actors.
If I am when performing doing real magic, I would start off as a normal trick slinging magician. People, normal people do not believe in magic. The shock of magic really happening would be a truly big reaction. You should not hit too hard at the beginning of a show (it’s called the big finale for a reason). It is good to warm up. I see a show like a story. There should be highs and lows. Things should build and you want people invested.
Another game I like to play while doing magic is to break exceptations. Also I like to give people what they want and expect so later I can break it. In the past before TV etc most people would not have seen magic. It is hard enough to see my favourite bands as I might not even know they are on tour, they may not come to my city and I might have something I am doing at the time that I can't cancel. People are at least aware of magic. When I ask them to choose a card, I do not even need to say don’t show me. When they put the card back in the deck and it get shuffled and I ask them what their card is, they give me a puzzled look and ask "but I am not supposed to tell you". I would like to say there is not rule book that states that the audience should hide the identity of their card with all their might. But people see it that way as that is the way magic normally goes.
That one question I ask for 2 reasons (as I am a two birds one stone kind of guy). The first makes them think that I can not do the trick without knowing what their card is. In turn it means I really don't know what their card is (just so you know I really don't). Second is to break magical norms in a benign way. To make them think is it really that important to tell me the card when right after I found it in one second? That not all tricks work the same way.
It means when I really do something out of the ordinary they are prepared for it.
Here is the other paradox that is not really.
I want people not to think about how it is done and just enjoy the show for what it is a show. But I want them to think for a split second, just for a moment "is this really just magic?” So I want them to think but not think? Hell Yeah I do.
To let go and just take the show in and not analysis everything is one of the steps for someone to see it as magic. Once you let your logical side rest the emotional side will play. Another way to do it is to break down expectations. Which yes is something I aim to do but not in the same way. To break down someone’s logical expectations until they are open to believe in magic is not something I want to do. It would it could end up breaking people beliefs in how the world really works, SCIENCE DOESN'T WORK ANYMORE is not something I want. Common sense is one of our most valuable tools, for example. Don't eat something you haven't seen before, look weird etc. It might kill you at worst. I also want them to question, I want them in fighting form to question too so not beating up their reason. Do not get me wrong a magic show can’t do crazy ass brain washing, but just because it can't doesn’t make it right to use the principles.
I on the other hand want them to let their logical side rest. I do it by breaking in small ways what they expect, building up. Because they don't know if I will do what they expect or won’t they hopefully stop trying to figure it out and just go with the flow. That’s the hope.
Basically I want to emulate what you get from a good TV show, movie or book. The characters are real and you care while the book is open, while the movie plays. Once it is over you come back to the real world and you not sitting their questioning if the evil villain will come back and enslave your family. The difference is I want people to say "what if it was magic" afterwards not "shit dude I think that was real magic". I want the discussion not belief, simply put.
I want that either way if I was doing real magic or tricks.