What is the ruling on praying two rak'ahs as a Sunnah after the Maghrib Adhan?

Two rak'ahs after the Maghrib Adhan are legislated, but they are not a regular Sunnah. This is based on the Prophet's (peace be upon him) saying: "Pray before the Maghrib prayer," he said the third time, "for whoever wishes," out of dislike that people might take it as a regular Sunnah.