I think the girl was worried she might be pregnant, told her sister and things went from there. She didn't run off after the encounter saying it was non consensual sex. It was not disputed that she had consented. The point about being 12 is that you cannot consent so any sex is rape.
I think this is an entirely exceptional case and won't set any precedent. He was lucky - if you can say that. My guess is if there wasn't the evidence of the stone-cold sober police and tax driver, the result would be different.
I think the verdict was correct in this case but in some ways I can see what joystir is saying. If you have casual sex with a stranger, you need to be prepared for anything - an STI, a partner or spouse popping up, a pregnancy with someone you don't even know, and yes, that she/he lied about her/his age.
I do judge whoever was responsible for that girl though.
There's always the possibility that she wasn't entirely straight with her parents about where she was going and who with on that particular night. They could well have thought that she was staying over with a friend. I'd like to bet they had no idea she was going to be out on the town and in a taxi queue being chatted up at 2 in the morning.
Yes it might happen, but when mine were 12 (and 13/14), I knew where they were having a sleepover, had checked in briefly with the mother and would be checking in by text too. Another poster said upthread about her 12 year olds 13 year old friends being out on the town and on contraception. Epic failing of those children.