OrchidsandLace: No, Pooch, I don't think either you or the man in this case are child rapists, since you both engaged in sexual activity with people you reasonably believed to be overage.
I can't believe you don't see the difference between these two situations. One involved a kiss in a public place, which should only be open to over 18s, with the adult immediately stopping when they realised how young the child was. The other involved full sex after a meeting at a taxi rank. Rather more time must have passed, giving the man in question the opportunity to learn more about the person he was shagging.
Seriously, the message we should be taking from this case is 'Don't have sex with someone without being sure that they're old enough to consent'.
And, no, I have never asked for ID, but I have always been certain that my partners are of age. And yes, if the man had asked for and been shown convincing fake ID, then I would expect that to be taken into account.