They met at a public place initially. Whether she had met him online or irl is irrelevant to her decision to go to his house - this was a product of her naivete.being nice to you once and then suddenly asking you to meet them in person alone.
I'll reiterate - there's nothing wrong with meeting someone you met online, in a public place. The issue here was not her meeting someone she had met online - the issue was that she got sweet-talked by a sexual predator.But, yeah don't just met random people you know online IRL suddenly without getting to know them for a few months or so.