Based on the story posted on this article, security staff confronted Nick upon his return to the hotel, questioned him about his visitant and asked him to register him at the desk.
This tragic death demonstrates why fathers and mothers spend so much time trying to convince their children that strangers very often equal danger, especially in somewhat dangerous cities like MEX. It shoud serve as a wakeup call to anyone, flight attendant or otherwise, who forgets that very bad things can happen when you make poor choices. And no matter how you slice it, bringing someone you just met in a bar to your layover hotel room is a poor choice.
To be sure, bad things can also happen to those who make excellent choices, but they probably don't happens quite as often as to those who make poor choices. I feel for his family.