Is it that rare?
Let's think about it:
Chances are that if you are performing somewhere, it is the kind of place that would have a magician. And, chances are, the people who show up are the kind of people who frequent those kinds of places. So, since these are people who are in the kind of places that would have a magician, chances are they've run into one before.
What that means is: when you do a trick that is popular, you are automatically inviting comparison. Now, if you are the bee's knees and KNOW that no matter what they've seen, you are totally better than whatever the other guy could have done - then there is nothing to sweat.
Otherwise, there is a chance people will leave your set thinking, "yeah he's good, but remember that other guy. He did that trick so much better. " Even if you ARE better, they still end up thinking about the other guy (who sucked) and they remember you as having done the same trick as the suckey guy.
Now, not everyone has seen magic in person, but a lot have. Why set yourself up for the inevitable if occasional comparison when, with just a little bit of work, you can avoid it all together.
Laziness and comparison vs. work and knowing you are giving your audiences something unique and special (you know, like magic)
Seems to me there's only one smart choice here.
Brad Henderson