Because I had a specific issue at a hotel recently, and because the hotel encourages reviews on sites - and specifically mentioned TripAdvisor - I decided to speak to management first.
That way, they'd know I was not thrilled with this one point, before reading about it online.

But then again, I have lived by the rule of "If it's great, tell your friends. If it's bad, tell the boss!"

I have noticed a few of my contributions no longer exist. Those were forum postings. But I honestly can't remember what the posts were about now. However, they were definitely subjects about things to do in specific cities, not reviews and nothing mentioned safety/security.
So I can't fathom why they are gone, they simply are gone. Maybe those forum subjects were closed for other reasons.