How do you figure? When you invite someone and permit them to bring a date, they can choose whomever they want.
This was a clever answer; at least if she can evade disclosing who the invitee was...
Ok, so the article said Chelsea must personally know everyone there. So if not Hillary, then Chelsea knew her or else the article was completely wrong....but...seeing as how Maxwell worked on the Clinton Foundation, I think its a pretty safe bet that they both knew her personally.