That isn't our policy.
The only rationale I can think of would be that there is a visual balance element to formations and choreography/routine placement. Height, hair color, and I suppose skin tone would be considerations in some instances. You generally don't want a 6' tall girl directly opposite a 4' 3" girl in a dance if you can avoid it. If someone has a very unique "look" (very tall, blue hair, only male, extremely fair skinned, etc.) then you usually either want them dead center or perhaps not highlighted at all.
That doesn't mean that there is a specific advantage in choreography to being tall or short (or light or dark), just that you want the "picture" to balance. Whether that would "help" you or not would depend on the circumstance.
There is MUCH more to determining placement than appearance, obviously. Where the athlete would be coming from in the previous formation would both be much more important in nearly every case. I also think that parents and athletes assign more value to "who is towards the front" than most coaches do. We tend to be much more concerned with getting people in and out of stunts/pyramids/baskets without chaos than making sure that Suzy is in front of Sally because she performs the dance .01% better.
