@LadyMarissa that sounds too much like the plot of a television drama to be real – but I’m not saying that you’re lying and that it’s a television drama; it just sounds very much like that. Can you give us a link to the news story, since this must have made the news somewhere?
But in any case, the girl you describe obviously did not “do everything that she could to protect herself”, especially when she agreed to meet him on the street and have him take her somewhere, according to a promise that she believed, and then she compounded that by simply jumping into a vehicle “because it appeared to be the one she had been shown”. Those are both pretty stupid behaviors, and I would question whether that girl was even old enough (or mature enough) to be on the streets on her own.
To answer the OP’s question more directly, I recommend asking “offbeat” questions or questions that take some thought to answer – “essay questions”, that is – and give answers of your own that may take some thought and additional questioning or conversation to fully understand.
It’s been said – partly in jest – that “Men talk to women in order to have sex with them, and women have sex with men in order to talk to them.” Like I said, it’s a joke, but it’s funny because at some levels and in some ways it’s true. So find out if the guy is at least willing to talk with you, to have an intelligent, thoughtful and meaningful conversation. Sure, he probably wants sex – that’s normal! – but is he at least willing to exchange some of his time, thought, consideration for you – and for your safety! beforehand?
When I’ve met women online I haven’t even considered “picking them up”. The idea of being “picked up and taken somewhere” by an unknown person is the stuff of nightmares. Even children know this.