In some scores, especially printed sheet music, “like” instruments in larger sections will be grouped together with sub-brackets, such as piccolos with flutes, oboes with English horns, clarinets and bass clarinets, etc. Here’s an example, cropped from a photo of one of my sheet music books (“Theme from Jurassic Park” by John Williams, published by Hal Leonard):
I’ve been Googling and reading various theory references, but I can’t find any clear indication of when sub-grouping like this should or shouldn’t be used. Some sources recommend it, others don’t say a thing.
Is there any consensus for when or where sub-grouping like this should be used, or is it a stylistic choice?