Recorded announcements are frequently made to remind passengers to report suspicious activity and not to leave their belongings unattended. Digital closed-circuit cameras (CCTVs) have been upgraded with recording software at all stations and trains operated by SMRT Corporation. Trash bins and mail boxes have been removed from station platforms and concourse levels to station entrances, to remove the risk that bombs will be placed in them. Photography without prior allowance was also banned in all MRT stations since.