Re: Write what you know
As an extension of Toby's point, I would say a lot depends on the POV.
If you're writing a detective or a medical person dealing with the body in the hotel, there's a lot more to be caught out on than if you're writing an interested bystander watching the goings-on. One needs details that the other wouldn't even notice or understand.
Sometimes it's the silliest minor detail that throws off your credibility. Last year I read the whole China Bayles series by Susan Wittig Albert (mysteries), and since I know little to nothing about herbs and such, her main focus is perfectly credible to me. But one little thing sticks in my mind long after the rest of that book has been lost to my terrible memory -- a character had a guinea pig that had babies, and they were described as ten or twelve little hairless things with their eyes stuck shut. I happen to know that guinea pigs have only a couple of babies, furry ones, with their eyes open, who start out eating solid food. A tiny bit of research would have uncovered that detail. And that's the thing I remember about that book, which is probably not what the author had in mind.