Delhi Metro Rail Corporation [Dmrc] — metro trains

Is there any check in the metro trains in general? As i notice everyday while travelling in pink line from shakurpur metro station to bhikaiji cama place that some passengers stand in the vestibule portion of the train from where the two compartments are joined. I have also noticed a sign there showing that standing there is not allowed. My suggestion is that if an additional can be made in the train that passengers are now allowed to stand there.