Answer: Yes. The security officers can still detain and search for weapons.
A MAGNETOMETER is an instrument used to measure the intensity and direction of a magnetic field. They are widely used for measuring the Earth's magnetic field, and in geophysical surveys, to detect magnetic anomalies of various types.
Due to the seriousness of an individual setting off the alarm of a magnetometer, the security officers have a right to detain and search. This is because a magnetometer is used to detect for metallic objects.