The usual reason happens to be a practical one: many find the rubber grips uncomfortable on their legs, pinching or just squeezing to tightly so they roll the hem up to eliminate the contact.
Bottomline as others have stated, wear what you like.
Gary Watts Vancouver, Washington USA
**************************************************************** The latest "fashion" thing I've seen is to turn the rubber gripper hem at the bottom of shorts up. Beats me.......... But in the end ride what you want. I personally could care less. Just hold your line at a steady pace.
Rob Dayton
Charlotte, NC
USA