Is the Witr prayer obligatory upon a traveler who shortens the prayers?

The majority of scholars used the Hadith of the Bedouin as evidence that Witr is a confirmed Sunnah and not obligatory. The Hadith states: "There are five prayers in a day and a night." He (the Bedouin) asked: "Is there anything else obligatory upon me?" He (the Prophet) said: "No, unless you volunteer." Some scholars are of the opinion that Qiyam al-Layl (night prayer) and Witr are the best supererogatory prayers, and the Prophet, peace and blessings be upon him, never abandoned them.