I cannot really tell of any danger I noticed here.
The sea is obviously one danger when you get into it, be aware that there might be strong current. A jellyfish is the other hazard, watch out where you swim and where you put your step.
1. The best is for yourself to compare at least 3 LAND PACKAGE COMPANIES' prices before making decision.
2. Hotels at Mui Ne may join hands with the land packages company and jerk up the land packages prices to you. They earn commission. And they dont record the prices on the receipt to you.
3. Dont trust them after you book the hotel with them and get cheated. BEWARE.
My hotel recommended bus was too old. Other busses from Mui Ne were much newer, and, I assume in much better condition. The lack of shock absorbers and non-functioning air conditioner vents made for an unpleasent experience.
I was getting a room at the counter... And I got a family room for $125USD since i was with my family. It the most expensive room there based on the printed price list the reception gave us. However when a caucasian couple came to enquire about the price, they quoted $190USD! Of course they left after hearing the price... so my suggestion will be to ask to see the price list to not be seriously overcharged... The normal rooms there are about $90USD?!
I was expecting a nice blue sea when i went to Phan Tiet... When i arrived the sand was beautiful... but the sea was a funny shade of brown which didnt look swimmable in... =_=... So if you are going there make sure you get a nice resort to stay in... I stayed in Saigon Muine and the place was nice enough... =)