It is a misconception to think that would-be terrorists are going to be deterred by the sight of airport-like screening of a random selection of commuters at MRT stations (MRT checks: How far should security screenings go?; Nov 16).

The Land Transport Authority has explained that this will not cause any delay to commuters as only a few are randomly picked for screening at any one time.

The tough question remains: How effective will such random checks be as a deterrence against someone who is, based on actual incidents in other countries, likely prepared to sacrifice himself in order to accomplish his mission?

If our random checks are focused on those with big bags, then it leaves open attacks by terrorists with suicide vests or those involving children. Terrorists with suicide vests are notoriously difficult to prevent or deter as they tend to detonate their vest upon detection.

Airport-like screening at MRT stations is good at weeding out only those with prohibited items, such as knives, and is useless against terrorists with explosives.

Such security measures are also likely to offend commuters as security personnel have a tendency to resort to racial profiling to pick commuters at random.

In this regard, it is more effective to deploy plainclothes police officers to conduct checks on suspicious characters in MRT stations and trains instead of having commuters walk through metal detectors.

Seah Yam Meng