For obvious reasons we don't get to see her, in order to judge how old she looks, but the problem here is that if one hooks up over the Net, meets up, and immediately, on that first meeting, goes off for sex, that's a risk one will be taking. I can possibly have some sympathy for those inadvertently caught, but it's limited because they didn't check by getting to know the other person first; they just jumped at the opportunity without regard.
BTW spath, those pictures tend to look to be of underage girls, even when it claims they are not. All the more reason to not jump into bed immediately, and for older girls/women who are lucky to look young, to carry age identity (or put up with the situation).