Westldnshawty, you have to be native Saudi to hold citizenship, what is your friend's nationality. The thousands of women who are maids in Saudi do not arrive or leave without Mahram i am sure, but Saudi women are considered special by the laws of their country and need permission from guardian to travel, seek education etc because they are considered dependents.
My cousin is a Somali Brit..
Plus I have two relatives who are not native Saudis and yet they have Saudi citizenship!
You can't hold dual citizenship if you become Sucuudi. Yes you can become a national but there are strict requirements.
1. You have to live there 10 yrs, with no misdemeanor
2. You have to be a professional who contributes to the sucuudi sector
3. You have to renounce your previous nationality if your a woman who married a sucuudi.
4. You can't be a palestinian refugee