What is the ruling on directing benefactors to widows and divorced women who later turn out to be exploiting aid to buy luxury goods, and is it obligatory to inform the benefactors of this?

One must investigate thoroughly before giving charity to the deserving poor. There is no sin upon someone who gives charity to a poor person whom they believed to be deserving, and it later becomes clear that they were not; their charity is still valid. This is supported by the Prophet's (peace be upon him) statement in the story of the one who gave charity to a rich person, a prostitute, and a thief, that his charity was accepted due to his good intention. However, if it becomes clear that someone is rich or spends money on luxuries, they should not be given charity. If a person is poor but foolish, spending money on trivialities or forbidden things, there is no harm in meeting their needs and the needs of their dependents through charity, but only with in-kind items such as food and clothing.