In the old days, a dignitary who admired the horse of a foreign prince might find himself given that horse as a present. The dignitary would then face a hard choice: keep the present and risk raising suspicions about whether he had been bribed, or reject the present and risk offending the prince.
One thing the dignitary would not do would be to accept the horse and then sell it. That would confirm that he had been bribed--that he valued not the deed of friendship and generosity by the prince but rather the cash it could be turned into instead. And that would offend the prince--tell the prince that the dignitary valued not the particular horse and its connection with the prince but the cash it could be turned into.
In these new days, we have Colin Powell:
A Saudi Prince Tied to Bush Is Sounding Off-Key - New York Times: A few nights after he resigned his post as secretary of state two years ago, Colin L. Powell answered a ring at his front door. Standing outside was Prince Bandar, then Saudi Arabia’s ambassador to the United States, with a 1995 Jaguar. Mr. Powell’s wife, Alma, had once mentioned that she missed their 1995 Jaguar, which she and her husband had traded in. Prince Bandar had filed that information away, and presented the Powells that night with an identical, 10-year-old model. The Powells kept the car — a gift that the State Department said was legal — but recently traded it away...
Prince Bandar ibn Sultan--or someone in his entourage--went to trouble to find a good-condition car of the same year and model that Alma Powell had said that she missed and to have it maintained and spruced up. It may have been legal for the Powells to accept the gift of the car and then sell it for cash. It doesn't seem to me to be ethical.