There are some rule for @CommuterLine passanger posted in some walls of the Commuter Train station. I found one of them in Tanah Abang Station. It is quite interesting, since they posted almost quite a lot in this station walls. Here are some rules that posted in the walls

• Every passanger including children above 3 years old, Military officer, Police Officer, and government officer should by a valid ticket for one trip
• Every passanger of the commuter train that have not any valid ticket will be imposed a 50 thousand rupiahs fine
• Please make sure that your ticket is in accordance with the type of the Commuter Train and also your destination. Keep safe your ticket when you travel, if you already bought a ticket and your ticket is damage or lost, you can not ask for replacement ticket
• No selling anything in the platform or inside the @CommuterLine
• You may smoke in the special space provided inside the station
• Every passanger of commuter train may bring a hand baggage with max size of 40 cm x 30 cm x 100 cm. Any long trip train passanger should follow this rule in accordance with their baggage
• You may bring a folding bicycle inside the commuter train with max dimension of 40 cm x 30 cm x 100 cm
• Do not bring any flammable, weapon, animal or  thins that create some very sharp smell and also any other things that forbidden by the law inside the station and also the commuter train