The New Jersey Symphony thought that philanhropist Herbert Axelrod was nuts when he offered to sell them a $50 million collection of instruments for $18 million, but they certainly never thought that, by agreeing to the sale, they would be running afoul of the United States Congress. But now, with Axelrod hiding out in Cuba from charges of tax evasion, “Senate investigators are questioning whether the instrument sale is representative of a fast-growing tax dodge in which wealthy donors inflate the value of gifts — from rare violins to paintings, period furnishings and even fossils — abetted by docile appraisers, weak tax enforcement and cultural institutions with little interest in making waves.”