He left a piece of blue luggage unattended at Hougang MRT station on April 2, sparking a security alert and the station's subsequent closure for close to 90 minutes.
As a result, more than 3,500 commuters were affected and nearly 700 had to be evacuated.
For causing annoyance to the public, Chinese national Wang Jianpo, 39, was fined the maximum $1,000 yesterday after he pleaded guilty.
The court heard that on the afternoon of April 2, Wang had collected the luggage from a friend before going to Hougang MRT station. As he wanted to go to Chinatown to run errands, he thought that it would be more convenient to leave the luggage at the Hougang station .
Deputy Public Prosecutor (DPP) Daphne Lim said a couple spotted the unattended luggage around 2.25pm and alerted the staff at the station control centre.
The operations control centre of the North-East Line decided to evacuate and close Hougang MRT station for public safety reasons. All trains were ordered to bypass the station, and the police were notified. Officers at the scene opened the bag and found household items. The station was reopened around 4pm, the court heard.
A total of 36 trains bypassed Hougang station as a result, while 29 buses, 15 SBS staff and 71 police officers were deployed to manage the situation.
After completing his errands, Wang took a train back to Hougang MRT station, and was arrested.
Urging the court to give him the maximum fine, DPP Lim said: "In this current heightened security climate, there is a need for this court to send a message that such acts involving the intentional leaving of one's personal items unattended at public places would be visited with appropriately severe sanctions."
Wang was represented by lawyers Ng Shi Yang and Ariel Lim from the Criminal Legal Aid Scheme Fellowship.
Mr Ng asked District Judge Kan Shuk Weng to fine his client $700, saying he was not a troublemaker. Added Mr Ng: "He was instead an ignorant fool. He had a simplistic approach to getting around his personal inconvenience, and a general ignorance of current affairs made him unaware of the recently heightened security climate in Singapore."
Four people were arrested in recent months for leaving items unattended at MRT stations. Wang's case is the first to be dealt with in court.
Referring to these cases, Mr Ng urged the court to calibrate sentences which reflect the differing culpability or ramifications of the acts. He said: "The sentence passed by this court in Mr Wang's case will be the guiding precedent for subsequent cases."