Most of the relatives and friends have said that Ms. Holloway would not have gone off with these strangers or she would not have gotten drunk. But as I said in one or more of the other threads -- people tend to do things on vacation they would not do at home. And that could be dangerous.
Rick Levanthal did a walk through report that showed there were camera everywhere on the street in front of Natalee's hotel. They were in the trees, drives to the hotels, streets, etc.
Suppose they slipped a drug in her drink that interacted with the alcohol, and suppose she was not truly in her right frame of mind? Anything of that nature is possible. Or that as the night wore on, she was having such fun dancing and socializing that she did not realize exactly how much she had had to drink, and was truly impaired in her judgement.
As to the issue of who the security guards work for, I think somebody could be splitting hairs, in that the men work for a security firm, not directly for the hotel.
Drugged by predators
Another thought -- does the date rape drug make someone act drunk also? Maybe something was slipped into her drink?