I could see someone using this on stage in Penn & Teller's Fool Us. The camera hidden in the table, on the table an elaborate box that never comes into contact with the cards, is used as some elaborate red herring (maybe you have to knock on it, or draw something from it), but really serves to hide a small screen.
Now you only have to come up with some impressive card trick that seems impossible to pull off with conventional methods.
Of course you could also come up with a better method to communicate the information than an ipad screen. Maybe a tactile signal.
The impressive card trick could would be the greatest of all time:
Have an audience member shuffle the deck to their hearts content, then place it on a table. Tell them what the top card is, then ask them to flip it to verify. Then proceed to do the same to _the entire deck_
Now you only have to come up with some impressive card trick that seems impossible to pull off with conventional methods.
Of course you could also come up with a better method to communicate the information than an ipad screen. Maybe a tactile signal.