Koh Bulon Leh is very safe and you will have more problems with protecting yourself from local wildlife than local people.
Ensure you bring enough mosquito repellent and good walking boots. Most hotels will provide a mosquito net but for eating dinner or walking in the jungle you will need either repellent or long sleeved clothes. Snakes can be a danger in the jungle but as long as you don't approach them and wear strong shoes the danger is reduced.
