It was prudent and necessary for police and SBS Transit to react the way they did after an unattended bag was found at Hougang MRT station on Sunday, security experts said.
A 39-year-old Chinese national caused a security scare after he left a bag at the train platform while running an errand. The bag was later found to contain household items.
The experts said the incident happened during a period of heightened threat of terrorism in the region.
"Trains and train stations... are 'target-rich environments' for terrorists to inflict maximum casualties," said Associate Professor Kumar Ramakrishna, head of policy studies and coordinator of the National Security Studies Programme at the S. Rajaratnam School of International Studies (RSIS).
"It was prudent to close the station to ensure no civilians would have been injured in the worst-case scenario of a bomb going off," he added, citing terror attacks on transport networks in the past, such as Mumbai in 2008 and London in 2005.
The station on the North-East Line (NEL) was shut for about 20 minutes after emergency forces were activated. The man has been arrested for public nuisance, with investigations ongoing.
Professor Rohan Gunaratna, who heads the International Centre for Political Violence and Terrorism Research at RSIS, said the authorities did not overreact. He added that it was essential to err on the side of caution, given the emergence of the Islamic State in Iraq and Syria terrorist group in the region.
"The Government will not take any risks and it will not relax its security after this incident," he said, although he noted that responses to such incidents should be calibrated.
Criminal lawyer Amolat Singh called for laws relating to such incidents to be sharpened to reflect the security climate.
"Currently, there is no such notice that you cannot leave your items unattended. It is arguable that this guy simply did not think it was wrong. Pinning him with an offence or punishments requires more clarity," he said.
Experts agreed the actions taken were in line with the national SGSecure efforts, with possible security threats at key infrastructure here.
Launched last September, the SGSecure movement aims to mobilise people to be more aware of security, respond to a terror attack and stay united after it.
Said RSIS associate research fellow Abdul Basit: "At the end of the day, no matter how prepared the forces are, commuters have to be alert as extra eyes on the ground."
In response to media queries, SBS Transit, which runs the NEL, said current security measures at its MRT stations and bus interchanges include deploying transit security officers and installing surveillance cameras.
"We also continue to review our security measures to ensure these are relevant in a dynamic security climate," said Ms Tammy Tan, SBS Transit's senior vice-president for corporate communications.
Transport operator SMRT said it works closely with the authorities, including participating in regular emergency preparedness exercises to practise response protocols.