In my opinion i dont think people nowadays think that magic really exist. If you take card magic for an example. I dont really think that laymen really think that you made the card jump to the top of the deck or that you really made it dissapear. In their minds they think that you are really skilled and you did something that their eye could not detect. Dont get me wrong i would really love for people to really belive in magic again, I do but the faq of the mather is that as time goes by we humans get smarter, atleast some of us.
Thats why we need singed cards, coins etc. To make it more convinceble. An illusion can only get better if the chances of you cheating is minimal. Thats why i love singed cards and coins. I dont really stress the mather of an card getting destroyed because of an signed card. And I think if thats whats keeping you from singing cards I think that you should take a look over your economy. Becasue decks arent that expensive. The best tricks that i perform are the ones that you really show the spectator that there really is their singed card/coin. It gives it that little extra touch that something might confuse them so much that there really is true magic. And is that not what we all strife for?
If we can just give them that 1 second of doupt then we have prevailed. That my opinion.
My main point was that people should not think less of an effect because it can not be signed or inspected, or you don't end clean. Work what you can do to your advantage.
I was just throwing out something why I tend not to have people sign cards, because of the deck thing. I get attached to a deck of cards., and tend not to use the performing one for any topological card effects.