Is it permissible for a person to provide a charity collector either a poor person, or a solicitor for an institution with information regarding a wealthy, generous person and advise that he approach him for a donation?
At first glance, providing this information violates the admonition in the Book of Mishlei (27:14), "He who blesses his fellow with a loud voice early each morning this is considered a curse for him." Rashi (classic commentator, France, 1040-1105) in Baba Mesia 23B, explains that information one spreads about his fellow's wealth is deemed a "curse" because corrupt people will now attempt to steal from that wealthy individual. A person should therefore keep such information private, rather than allow it to reach the ears of potential criminals. Likewise, Rashi adds, if people hear that a certain individual is a man of wealth, they may flock to his home and invite themselves in, thereby depleting his resources.
Seemingly, then, we should forbid divulging information about a person's wealth to a charity collector.
In truth, however, Rabbi Moshe Feinstein (Russia-New York, 1895-1986) in Igrot Moshe, Y"D, Helek 3, siman 95, ruled that the concerns addressed in this verse do not apply in the context of a charity collector. According to Rashi's first interpretation, the concern is that dishonest people and thieves will devise schemes to steal the wealthy man's money. This concern does not arise in the case of upright, decent people, and therefore if a person knows that the charity collector is honest and decent, he may refer him to a potential donor. As for Rashi's second explanation, the concern is that people might invite themselves into the wealthy man's home and he would be too ashamed to turn them away. In the case of charity solicitation, however, there is no shame involved in refusing a request or giving a lower amount than the solicitor requests. In fact, Halachic sources mention that solicitors for a communal charity fund are allowed to approach all members of the community, and need not be concerned that a given member might feel too ashamed. Refusing a request or making a modest contribution is not looked upon as a source of embarrassment, and therefore we need not be concerned that a wealthy man will feel too ashamed to refuse the request of a solicitor.
In conclusion, then, one may refer a charity collector to a wealthy individual, provided that he knows this collector to be an honest, decent and upright person.