I actually worked a qualifier for the Women's National Yeam once. At that level they placed a divider diagonally across the table to prevent partners from being able to see and signal each other.
Personally I think it would be very hard to get to that level by cheating, as you end up with anomalous results (not only were they recorded, but pretty much any competitive player at the regional tournaments could rattle off every single hand and result after an afternoon of 26 hands of bridge).
It was good work, paid really well for a 13-15 year old, and I even learned enough bridge to play on the rare occasion I'm with 3 other like minded people.
side note: for those not familiar with duplicate bridge, you play the same hands as other players. The hands are scored similarly to rubber bridge, but your actual points for ranking in the tournament are based off of how much better or worse you do than other people.
In matchpoint play, many people play the same hands, rotating opponents and there is a formula for calculating the score.
In team play, 2 from your team play against 2 from the other team, and then you switch the hands so that you get the cards that the other half of your opponents team just had. Typically this is done in a sequence of rounds in a Swiss format[1]