How about puncturing the tires before abandoning the cars? Break the windows. Tear the seats. Take the steering wheels out. Do anything. Just don't leave the cars in one piece for Houthi militants to drive away in and making out like bandits.
An excerpt from, "Yemen Houthi rebels seize U.S. embassy vehicles after diplomats leave: staff" Reuters, February 11, 2015:
Armed Houthi rebels in the Yemeni capital Sanaa seized U.S. embassy vehicles after the ambassador and diplomats left the country on Wednesday, local members of embassy staff told Reuters.
The employees said that more than 20 vehicles were taken by the fighters after the Americans departed from Sanaa's airport.An excerpt from, "Al Qaeda Seizes Army Base In South Yemen" by Aditya Tejas, International Business Times, February 12, 2015:
The United States, Britain and France have closed their embassies and evacuated staff as the security situation in Yemen has unraveled following the group's formal takeover of power last week.
Al Qaeda militants attacked and captured an army camp in Yemen on Thursday, leaving at least eight dead, The Associated Press reported. A Twitter account associated with al Qaeda in the Arabian Peninsula (AQAP), al Qaeda’s Yemeni franchise, reportedly took responsibility for the attacks.
The camp of the country's 19th Infantry Brigade was seized in the town of Baihan, about 200 miles east of the capital, Sanaa. Of the dead, at least four were army soldiers, AP reported, citing army sources. The group also posted images online, showing militants raising their black flag over the base, and inside armored vehicles. The AP said the authenticity of the images could not be verified, but added that they correspond to reports from the scene.