taxi line-ups

Why at places such as the Adelaide Casino and Adelaide Airport (and I am sure other areas) do the taxi's go about the inefficient business of only picking up the people at the front of a bloody long line?

I understand the fairness involved with queueing but it'd make a lot more sense for people from throughout the line to get into cabs, who are level with them so a whole fleet of cabs can move off the rank at one time, rather than just one or two and then having more cabs come back. When the line is relative short, then people can go in order. But wake up and smell the coffee beans... it is a much longer process to only pick up the person right at the front when the cabs are forming a bloody great line that stretches back quite some way.

Efficiency and then fairness would actually get everyone home a lot quicker, no matter where they were in the queue. (Or they could have people with radios 'air traffic controlling' the taxis and queue as they do at Sydney airport). The inefficiency and insecurity that a persons place in queue is more important than them actually getting home faster drives me nuts.