I got tripped up by visa regulations here a few weeks ago. Showed up in DXB on a BA flight from London with a female traveling companion at about 11:00 p.m. and didn't know about the visa requirment. As a result, we spent five hours in the holding area while our hotel (Hyatt Regency) ran around and obtained "emergency visas" at great expense. Then, when we got to immigration, the officer told my friend that unaccompanied females were not allowed and that I would have to pose as her husband!!