We detached this subthread from https://news.ycombinator.com/item?id=13830706 and marked it off-topic.
Tourist couple arrested in Abu Dhabi for sex before marriage after police discover woman is pregnant
http://www.mirror.co.uk/news/uk-news/tourist-couple-arrested...
update: It seems the restriction on women traveling who don't have husbands/fathers has been relaxed/ended. Looking more into it.
Update 2: On UAE Embassy for US no mention of restrictions But not the case for other countries.
For Indian women one provider states: For female applicants and students who are above 18 years and travelling alone require NOC from parents / husband, Photo ID of parents/ husband. Coloured copy of the host passport / residence visa
With little googling you can find a reason behind this. Dubai escorts is huge.
(I know you may be stating their reasoning and not I am not saying you are endorsing that)