of course no man would ever attempt to attack a girl out wandering the streets in the middle of the night when she has the protection of eh some other young girls.
She is with a group of boys and girls. I do think it's unlikely a man would attack her as a member of a group of people, some of whom are 6ft+ lads.
If you believe that why not let your 15 year old go to nightclubs, sneak into pubs and get drunk, go back to random people she doesn’t know houses for house parties, watch porn? All also exposures and risks.
You've missed the bit where I said assess the risks and benefits. The benefits of going to a nightclub / pub / getting drunk / going to strangers' houses / watching porn at this age do not outweigh the risks. Whereas imo, the risks of being out in a safe place close to home with her friends are very low, and she is gaining independence, having shared experiences, deepening her friendships, getting out of the house, spending time out in the world instead of watching tv or being online, becoming herself away from us, growing up and having fun.
The downside for us is as a PP says, having to stay sober so that we can pick her up, but for such a short time it's worth it. Especially as my saintly DH volunteers most of the time 