i have a few things to note on this. i've helped my friends promote parties back when i was in the clubbing scene and have some insight into what typically happens.
Typically the scenario in which this happens is when there's too many guys already in the club and we're trying to correct the ratio. That is when we used to get really selective about the guys getting in. Now I'm hardly racist towards indians (or other south asians) but the younger guys usually travel in large groups as opposed to other races.. fairly aggressive groups i might add. this always meant trouble. now this was in canada, where the male/female ratio is not even close to being as skewed as it is here. so you can imagine how hard it is for an organizer to keep up a good ratio. if i see a group of 5 indian guys and 2 australian guys, i'm much more liable to let the australians in simply because i can't break up the group of 5.
the other scenario is when you are aiming for a certain "clientele". This is where we tread a fine line between racism and social casteism. it's about how the person is dressed and how they carry themselves. i've beent to clubs in toronto dressed pretty badly sometimes, knowing that i'd never have gotten in if i didn't know the promoter.
the final scenario is the purely discrimnatory one. never faced that in dubai so far, but i did once in toronto. we still got in though... persistence pays
. so does a twenty in the palm of the bouncer 
