Crouching tiger, hidden donkey

A restaurant in northeastern China that advertised illegal tiger meat dishes was found instead to be selling donkey flesh — marinated in tiger urine. The restaurant was fined even though donkey meat is widely consumed and not illegal in this region of China. The nearby tiger reserve has sold dead tigers and been involved in similar controversies in the past, which makes you wonder if the donkey flesh was in fact tiger. Also, exactly how does one obtain tiger urine?