I would like to see the weights tracked and posted...Other tracks in other countries do this, notably, I believe, in Hong Kong, and the commentators there routinely reference weight changes/ amounts as part of paddock profiling...
I can think of at least one reason: The Alpha Horse, herd animals, you know, the biggest, tallest, strongest horse in the pack...maybe the others just tend to follow, even if he is not always, the fastest...