Bali Bill who's been here since 71 says that back then if there was any theft it was most likely someone from Java and if caught they were stoned to death on the spot. He says he witnessed such a stoning in Ubud.
When I was here twenty-two years ago I heard of five separate cases of thieves beings stoned or beaten to death by an angry mob. Every case was workers from Java. Two had robbed suitcases from some German tourists. They were pulled from a police car and pummeled to death on the spot.
So back then the thought of taking what was not theirs did not occur to almost all Balinese people. Bill identified a few factors in the erosion of honesty on the part of the local culture. One is an infusion of Indonesians from other islands, mainly Java. Another is rubbing up against Westerners. He told about a woman who mortgaged her rice paddies to make three container loads of items made from dried flowers, shipping them to Italy, being told she wouldn't get paid till she sent the papers to release the imports at the docks, and then never getting a cent and loosing her land. He said he'd seen that story retold many times. He added that the shifting of authority from local hands to police departments meant that thieves now could bribe police or serve short sentences and be back out.
I'm still glad they don't stone thieves here anymore.