Bureau of Consular Affairs, U.S. Department of State:
Saudi Arabia
Country Specific Information:
. . .
STANDARDS OF CONDUCT AND RELIGIOUS POLICE: Islam is the official religion of the country and pervades all aspects of life in Saudi Arabia. Public display of non-Islamic religious articles such as crosses and Bibles is not permitted. Travel to Makkah (Mecca) and Medina, the cities where the two holiest mosques of Islam are located, is forbidden to non-Muslims.
The norms for public behavior in Saudi Arabia are extremely conservative, and religious police, known as Mutawwa, are charged with enforcing these standards. Mutawwa are required to carry special identification and usually are accompanied by uniformed police; however, in some cases they have detained persons even without police presence. To ensure that conservative standards of conduct are observed, the Saudi religious police have accosted or arrested foreigners, including U.S. citizens, for improper dress or other alleged infractions, such as consumption of alcohol or association by a female with a male to whom she is not related. While most incidents have resulted only in inconvenience or embarrassment, the potential exists for an individual to be physically harmed or deported. U.S. citizens who are involved in an incident with the Mutawwa should report the incident to the U.S. Embassy in Riyadh or the U.S. Consulates General in Jeddah or Dhahran.
The Saudi Embassy in Washington advises women traveling to Saudi Arabia to dress in a conservative fashion in public, wearing ankle-length dresses with long sleeves and not pants. In many areas of Saudi Arabia, particularly Riyadh and the central part of the Kingdom, Mutawwa pressure women to wear a full-length black covering known as an Abaya, and to cover their heads. Most women in these areas therefore wear an Abaya and carry a headscarf to avoid being accosted. Women who appear to be of Arab or Asian origin, especially those presumed to be Muslims, face a greater risk of being confronted.
Some Mutawwa try to enforce the rule that men and women who are beyond childhood years may not mingle in public unless they are family or close relatives. Mutawwa may ask to see proof that a couple is married or related. Women who are arrested for socializing with a man who is not a relative may be charged with prostitution. Some restaurants, particularly fast-food outlets, have refused to serve women who are not accompanied by a close male relative. In addition, many restaurants no longer have a “family section” in which women are permitted to eat. These restrictions are not always posted, and in some cases women violating this policy have been arrested. This is more common in Riyadh and the more conservative central Nejd region. . . .
http://travel.state.gov/travel/cis_pa_tw/cis/cis_1012.html
and if that’s not a place for a rip-roarin’ vacation, I don’t know what place would be!