(Image: Victoria and Albert Museum)
It's Istanbul in the Seventeenth Century. You, a nobleman of refined peerage and accomplishment, have been invited to visit the Sultan in the Topkapi Palace. As the Grand Vizier of the wealthy and powerful Ottoman Empire, this not a surprise, as you have visited there often.
When you arrive at the palace, you are, according to custom, served sherbet. In the past, the sherbet has always been white. But now it is red. Your blood runs as cold as the sherbet because you know what the color means: the Sultan has ordered your execution.
The gardener steps forward to carry out the duty traditionally given to him.
But wait! There's still a way out. According to Ottoman law, you may escape execution by outrunning the gardener/executioner in a 300-yard foot race. Smithsonian magazine describes this custom maintained by the Ottoman Empire for centuries:
For a grand vizier, however, there was still a chance: as soon as the death sentence was passed, the condemned man would be allowed to run as fast as he was able the 300 yards or so from the palace, through the gardens, and down to the Fish Market Gate on the southern side of the palace complex, overlooking the Bosphorus, which was the appointed place of execution. [...]
If the deposed vizier reached the Fish Market Gate before the head gardener, his sentence was commuted to mere banishment. But if the condemned man found the bostanci basha waiting for him at the gate, he was summarily executed and his body hurled into the sea.
-via VA Viper
It honestly sounds like a retrofitted law. A Grand Vizier escaped by fleeing the executioner, and the Sultan explained it by "a little known rule," which then became enshrined forever.