Walking through Akihabara you'll see images of 'school girls' everywhere, and often maids, too. There are a lot of girls dressed up in little outfits standing outside the shops and arcades, often in cosplay.
In most cases it's not sexual/sexualised. It seems weird and hard for us westerners to understand that a girl dressed scantily as a maid or as a school girl with knee-high stockings isn't meant to be sexual, but most Japanese view it is kawaii, a type of 'cuteness', which is enjoyed by men and women alike. You can even pay some of these girls to hug you - again, not meant to be sexual, but comforting. It's a weird concept and quite an unconformable one for westerners at times, but that's just how it is there. I've never suffered a culture shock quite like that which I experienced in Tokyo, it was overwhelming at times.
However, there are certainly cases where it goes a bit darker; the signs which point you down towards shops and establishments in basements and side streets are usually a good clue. It's becoming more prevalent, too, especially with the increased immigration to places like Tokyo (lots more dirty western men, and more Filipino/Thai/Indonesian girls going there to work and being treated like shit by the Japanese).
I usually can't stand Stacey Dooley - how she ever got this gig is beyond me - but I might have a watch of this later, sounds interesting.