I have also done Shape Shifter for many years and no one ever said anything, or hinted how it was done. Laymen are not as determined to figure out tricks as magicians are, which leads to a magician over-thinking not realizing just how much knowledge that they have obtained over the years. Since I have been in magic so long I rarely ever see anything that fools me, and I am able to watch effects without a critical magician eye. Took awhile to be able to do that, but it is important so that you are able to enjoy magic and see it the way spectators see it. You have to turn off "magician mode" and see the trick how it is supposed to look, and look where you are supposed to look.
I used to only watch magic from a magician's point of view and it was pretty boring. So I worked on forgetting what I know, sort of like a self-hypnosis technique; and this allowed me to enjoy magic again. Most spectators are just watching to be entertained, and have no clue what is coming. Magicians watch something a million times if they have to, and don't sleep for weeks until they worked out a possible method. Spectators usually do not care, and forget it eventually as they have their own thing to do. So as long as you put the work in and practice and rehearse effectively you will be fine. If something even slightly fools me I cherish the moment. But there are only so many principles. I watch first as a laymen, and as a magician later. I always hope I am fried by an effect so that I can savor the moment for as long as possible, and go back to that time as a kid where wonder seemed so real.
Most specators are not there to backward engineer all of your tricks. And if you are proficient at what you do, and they have never seen the trick before, you have a huge advantage. Sure you get the occasional heckler or idiot, but those are far and few in between if you are doing your magic properly. Reminds me of one of the many essays that I wrote years ago, "Magicians Being Fooled" viewtopic.php?f=10015&t=133659