The other day, after watching a play at the Nehru auditorium, a friend and I had to use the washroom. As the play had just ended, there were naturally a lot of women wanting to use the washroom and consequently, a longer queue. There were a lot of toilets inside the restroom and people had made a single queue outside the restroom rather than queues outside individual toilets, and were following FIFO (First-In-First-Out) which as per me, is the fairest way of queue formulisation when it comes to restrooms. With restroom queues, there is always that uncertainty as to how long a person will take and a queue outside every toilet inside the restroom would not be fair if a particular queue went faster than the others just because people took less time. With queues that follow a fixed time limit of service, multiple queues are okay. 

I googled for such a formulation before posting it up here to see whether someone else had already done so and this is what I got: http://www.credmond.net/projects/unisex-bathroom-problem/ It describes the queue problem for unisex bathrooms but follows a FIFO strategy too.

Unfortunately, this is not followed in restrooms in a lot of malls & multiplexes here.