You have to take and pay for escort for Ramlat-as Sabatayn aka Rub-al Khali Desert which is provided by ministry of interior. Desert is between Marib and Shibam.
When we were there (2003) we slept in Bedoun tent with bedoun escorts.
Infact it was told to me that, kidnapping tourists is not an act against tourists but is a way to find a solutin as forcing government against disagreement or problems between tribes.
It is true, if you are kidnapped they vehave you very well as a guest. You like it
at least the ones who were kidnapped says they treated ver well... and no cost too ;-) May be a good opportunity to know Yemeni people up and close.
Hadramut is the dangereous area though I think it is not dangereous as before.
"where the traveller goes, nobody knows ! "