[fenomas]

The default case is the that the contestant's trick isn't original to them, and Penn just gives the trick's trade name or its inventor's name, obfuscated a little, and the contestant grins and waves goodbye.

When P&T actually make a guess about an original mechanism, sadly Teller either whispers it or draws it on some paper that they then dispose of in some suitably flashy way. (He's usually right of course!)