Behind the cuddly facade lies a cunning thief
Bali has been the scene of lethal terrorist bombings in 2002 and 2005, both waves of attacks targeting nightclubs and restaurants popular among foreign visitors. Security is consequently tight in obvious targets, but it is of course impossible to protect fully against terrorism. If it is any reassurance, the Balinese themselves — who depend on tourism for their livelihood — deplore the bombings and the terrorists behind them for the terrible suffering they have caused on this peaceful island. As a visitor, it is important to put the risk in perspective: the sad fact is that Bali's roads are, statistically, far more dangerous than even the deadliest bomb. It is still prudent to avoid high profile western hang-outs, especially those without security measures, and the paranoid or just security-conscious may wish to head out of the tourist enclaves of south Bali to elsewhere on the island.
Bali is increasingly enforcing Indonesia's harsh penalties against importation, exportation, trafficking and possession of illegal drugs, including marijuana, ecstasy and heroin. Several high profile arrests of Westerners have taken place in Bali since 2004, and a number have been sentenced to lengthy prison terms or execution. Even the possession of a small amount of drugs for personal use puts you at risk of a trial and prison sentence if searched. Watch out for seemingly harmless street vendors looking to sell you drugs (marijuana,cocaine, etc.). More often than not they are undercover police and will try to sell you drugs so that they can then get uniformed officers onto you and demand a bribe (anything from Rp200,000-1,000,000) to let you go.
In Bali if you see a red flag planted in the sand, do not swim there: they are a warning for dangerous rip currents. These currents can pull you out to sea with alarming speed, and even the strongest swimmers cannot swim against them — the thing to do is to stay calm and swim sideways (along the shore) until out of it, then head for the shore.
Last but not least, be wary around the monkeys that infest many temples (most notably Uluwatu and Ubud's Monkey Forest). They are experts at stealing possessions like glasses, small cameras and even handbags, and have been known to attack people carrying food. Feeding them is just asking for trouble.