Various campaigns and activities are taken to help ensure that the MTR is a safe system to travel on. Poster campaigns displaying information on topics such as escalator safety are a common sight in all MTR stations, and announcements are made regularly as safety reminders to travelling passengers. By-laws were also introduced to deter potentially dangerous actions on the MTR, such as the ban on flammable goods on the MTR and rushing into trains when the doors are closing. Penalties ranging from fines to imprisonment have been imposed for such offences.