WESTPORT, Conn., Nov. 19 — A Crystal Rock water bottle is Exhibit A in a campaign to reduce cheating here at Staples High School, a bastion of affluence, academic achievement and unrelenting pressure to succeed. The label of the bottle had been peeled off, the history of atomic theory printed on the back and the label restored in preparation for a chemistry test. The test taker hoped for a handy crib sheet — indeed, it was even magnified by the water. But it also turned out to be easily visible to the teacher, who was more alert than he was...