A convoy of dozens of motorcycles circled East Java's town of Madiun nearly every day last week. Most of the riders wore a white and gray uniform. The roar of their vehicles' engines deafened people's ears. Smoke out of the mufflers formed a black fog that suffocated and smarted eyes. But oddly, not one police officer was seen to drive them away.

This public disturbance in the town known for its brem (fermented sticky rice cakes) became a freq