See those bars up top? I'm pretty sure I'm part of the reason why those are there. Those used to be open air when I was in my early 20's and broke all the time. A bit of urban gymnastics, and one could up and over that section. The reason why this was ideal over just jumping a turnstyle back then was because it was far less obvious. These are tucked away in a corner by themselves (depending on station), and I don't think they had the same number of cameras back then. The downside is that the tops of those things are covered in decades of grime and bird shit.