You did the right thing, Drummer, and I'd be surprised if you didn't help her in the process. She could have had psychiatric problems, for sure, but - I'm presuming that she's there with her parents? How many 16-year-old girls with psychiatric problems are left to walk around caravan parks in their pyjamas, hugging and harrassing strangers?
Her parents must have some idea of how screwed up her behaviour is - and some idea that sooner or later she's going to get herself sexually assaulted in the process. It may be just me that thinks that leaving someone who behaves like that to their own devices - most likely just to get a bit of peace and quiet - doesn't entirely fit my definition of "responsible".
Sorry if I come over as a bit right-wing and judgmental here, but I'd say you gave her a better-late-than-never lesson in the concept of "boundaries".
Not at all. I wholeheartedly agree: it's not about being right-wing or anything; this girl sounds seriously screwed up and this behaviour urgently needs dealing with - otherwise, if she continues to behave like this in public she'll probably end up being raped at the hands of some sicko.
To the OP: you did good.