In my library I see more girls barefoot because we tend to wear shoes without socks but have noticed if Girl are wearing socks they leave them on but boys are more likely to take socks off .
Back in college I'd sometimes take off my shoes in the library when studying. Almost never wore socks -- I've always hated socks -- so getting barefoot was easy. As far as whether a guy or girl is more likely, I imagine it's girls.
I don't know about any other girls or boys. But I went to my local library barefoot just last week. In fact, for the past 7 weeks now, I've been barefoot everywhere, nonstop. Even at the bank, where I usually wear sneakers so as to not look like the village idiot. But after several weeks of almost non-stop +30 degrees °C weather (86 Fah), I'm pretty sure they understood where I was coming from.
I'd probably say girls but could also depend on the school and the culture. When I was in school it was an even split between girls and boys.
Girls Becuase they shoes without socks But Girl who wear socks are less likely to take the socks off than girls