Modus Operandi

I saw this group of people during my visit to Burnham Park and I remembered a similar situation when I was tricked in Cubao during my high school days.

How does this modus operandi work?

1. You, the curious one, approach and observe these deeply thinking people trying to solve a chess problem.
2. The Dealer, then tells everyone that you will win money if you solve the problem by only 3 moves.
3. You, the smart one, thinks deeply and tries to simulate the moves to