IT IS MORE FEMALES THAN MALES WHICH LOOK OUT FOR OTHER FEMALES SAFETY.
I grew up in Brisbane, Australia and lived most of my adult life in London, Milan and Singapore, and have back packed most corners of the globe. On the whole, whilst I have been street savvy, I have not been concerned for my safety - even when travelling parts of the world where it is a significant issue for local women. I think the key difference being that I did not fear for it from a young age, which is not the case in other parts of the world. As I reached my teenage years, and fear was expressed from parents, my female community kept an eye out for each other, and I now realise even more so than our male community of friends - unless it was your boyfriend... but even then, I think it was more your girlfriends.
In writing the above, it only now occurs to me how much more the girls look out for each other, which is great, but it raises the question for as to why male friends are not as sensitive to this??? - even in developed markets.
My experiences have been that when you put a girlfriend in a taxi, you always let the taxi driver know you have his taxi number, or you get your friend to talk to you on the mobile on the way home, or to text you when home safely. Obviously you are the wing man in social environments and save each other from uncomfortable situations.