Fare evasion
Fare evasion, or ticket evasion as distinct from fare avoidance or ticket avoidance, is the act of travelling on public transport in disregard of the law and/or regulation, having deliberately not purchased the required ticket to travel (having had the chance to do so). It is a problem in many parts of the world, and revenue protection officers operate on many systems. Often ticket barriers, manned or automatic, are in place at stations etc., to ensure only those with valid tickets may access the transport.