DR. JOHN INVESTIGATES Part 2........

My latest research on cheating at bridge attempts to explore the environmental influences on players which create in their minds the perfect conditions to get away with unethical bahaviour. Crimes are more likely to be committed when detection is most unlikely.  Ideal circumstances include busy noisy  backgrounds, crowded dimly-lit rooms , lots of distractions going on , lack of policing , and unobservant victims. Take a crowded underground train for instance ( standing commuters packed in like sardines, unable to move, forced only to stare ahead ) where the conditions provide a paradise for pickpockets to go about their business.   If cheats believe their actions will be unseen and anonymous, with very little chance of being caught, the temptation to cheat becomes all too great. 
It is my contention that bridge rooms are like crowded underground trains : a background of noise from table conversations , arguments with raised voices , moving chairs, constant coughing and screaming calls for the director. So when players try to shut out this background noise they often shut out what is going on under their very own noses. Compelled by etiquette NOT TO STARE OR LOOK at opponents , the conditions are perfect for bridge cheats to apply their trade . 
Moreover , players are also prone to cheat when they are feeling tired, either physically or mentally, and long sessions at the card tables do take their toll on players' mental stamina , which is often in short supply. The game of bridge by any standard requires high levels of focus and concentration : it is a very demanding and tiring game. Players will inevitably succumb to tiredness , and as a result the temptation to cheat becomes almost irresistible. Although players don't cheat spontaneously when sleepy or drained , their honesty and self-discipline are severely tested. Even more so in circumstances where their self-control is also badly depleted , and the pressure to get a really good board has reached crisis point.