Black Widow

A customer asks how quickly can it be re set - they want to use it for a mindreading effect, where an audience member supplies a coin and places it face down on their hands, Black Widow then switches the coin for an identical coin, however the magician will then know the date. The volanteer is asked to look at the date and concentrate on it and the magician will get the date by thought transmition.

Now if this is to be done table hopping - How easy is it to replace the coin that is to be substituted?

It's super easy. If you're talking about taking the spectators original coin that you've walked away with and reading the date on it, then putting it back so you can do it again then it could be done in a second.

I don't know if it could really do this with out it being noticed, but the reset is non-existent.