Yes, he believed the covert cheating device was an industrial-strength vibrator powerful enough to visibly shake the chair she was sitting in. Because that wouldn’t arouse suspicion. Truly a brilliant theory by Doug.
You have to give the "lawnmower engine vibrator" hypothesis some credit for its sheer hilarity. Imagine Lew sitting there getting signals loud enough for the entire table to hear, see, and feel, like the water cup in Jurassic Park
https://youtu.be/xPQUarLEr9A