Natalee wasn't stupid. She was just nieve in that she would have never thought she was going into a bad situation. I've been there in my younger days and can't believe i walked away from something that could have turned horribly wrong. She wasn't stupid. She was a very bright girl who just was having a good time and didn't think she could have gotten into trouble. It is sad really. Even the smartest person can be nieve in a situation if they have never faced it before.
No, Natalee wasn't stupid. She was too trusting, or naive as you say. I have no doubt at all that many young people have used bad judgement and it did not begin in 2005 for sure. Most come home safe and sound. When they eventually mature, get some wisdom, it's then that they realize the risks they took.
Forgive me for quoting a well-worn adage: You can't put an old head on young shoulders. Too bad. Imagine the pain we'd be spared!