In an era when mega-millionaires are made — and unmade — faster than ever, nonprofit cultural organizations are becoming more cautious about whose money they take, the New York Times reports.

The recent arrest on fraud charges of arts benefactor Alberto W. Vilar would seem a cautionary tale for arts institutions around the country. Vilar, a technology investor whose net worth has tracked the ups and downs of the stock market, made several large pledges to concert halls and opera companies, including the Metropolitan Opera in New York City, only to leave them hanging.

Similarly, after two trustees of the Whitney Museum of American Art in New York City — Jean-Marie Messier, the ousted chairman of Vivendi Universal, and L. Dennis Kozlowski, the former chairman and CEO of Tyco International — fell from grace, the museum launched a legal and ethics committee to screen potential board members.

"Everyone's being much tougher these days," said Michael Margitich, senior deputy director for external affairs of the Museum of Modern Art in New York. The museum's board, he added, "likes people to go through a long courtship" before enlisting trustees; donors usually join a committee first, and then they gradually become involved with the institution before being asked to join the board, a process that can take anywhere from two to five years.

According to arts executives, long-term relationships serve as a kind of donor insurance. The longer you know a prospective donor, they say, the more you can rely on his or her word. Conversely, the more extensive an institution's history with a donor, the more forgiving it is likely to be if a donor's fortunes take a turn for the worse.

Fortunately, these same executives add, donors generally do come through, and defaults are rare. If defaults on pledges have been getting more attention of late, they note, it is because the money at stake seems to be bigger and more quickly acquired than it was in the past. But they are also quick to point out that the Metropolitan Opera's experience with Alberto Vilar — the company relied on a $4 million pledge from Vilar to underwrite two of its most extravagant productions; when he failed to come through with the money, it was forced to create a bad debt reserve to cover its costs — offers an important lesson for institutions everywhere: Wait until you have the cash in hand before you spend it.