I would dispute that most people will be watching on video - unless they have recorded a street show (which happens), or I upload a video that I have recorded myself, and I'm unlikely to do that if there is a _glaring_ load flash.
Also, by the time you get to the big loads, the audience should have been conditioned to your direction so that they are not burning your hands. If this is not the case, flashing loads are the least of your problems!
Time to quote Carney again: When I was younger I thought that technique was everything, and misdirection was insurance against poor technique. Now I know that the opposite is true.
If you have a spectator who is going to burn your hands throughout the performance, they are unlikely to enjoy the show anyway, because they are treating it as an intellectual challenge. Whether that is a symptom of their personality, or the magician's presentation style, I would direct more of my efforts towards entertaining the rest of the audience; the burner is more likely to be brought along with them.
Slightly related story; many years ago I was doing a small close up show in the Fringe. Twenty seats around a table, not unlike the close up room in the Castle. A couple came in and sat in the two seats to my right - the hot seats for the show - and announced that their son did a little magic, so they know what to look for. Very much a challenge attitude, but I laughed it off and got on with the show. Towards the end, I was going through a card under cup routine (using my chop cup that had featured earlier) and after the third time the card ended up under the cup right in front of the couple the woman turned to her husband and said, quite loudly, 'You are supposed to be watching him!'
Moral: sometimes, the people who think they know about misdirection are the easiest people to direct