A great article from 1934 issue of Modern Mechanix about all the nasty tricks carnies pull.

Cries of “Try your luck” still meet with ready response despite the fact that one might as well back a three-legged horse to win the Derby as to buck the carnival games and gyp wheels. But the gullible bystander persists. He believes that luck and the law of averages has something to do with it-and he’s right; but the luck is all with the operator. The playel’ doesn’t stand a chance. He can’t win because the games are set against him.

How Carnival Racketeers Fleece the Public [ModernMechanix]