About a month ago, East Hampton Mayor Paul F. Rickenbach Jr. issued a reminder to groups of bicyclists who might take to his village’s roads. Objecting to thick knots of organized recreational pedalists who fail to yield to motorists or force pedestrians to jump aside, Mr. Rickenbach reminded them that they, too, are obliged to follow traffic laws, just like the drivers of cars and trucks, “in such a manner as to prevent undue interference with the flow of traffic.”