Originally Posted by oneofthosepeopleyouloveto hate

Oooh, the mag ...

The main checkpoint I work at is on the 2nd floor, and the commercial curb is directly below us ... sometimes, when a big bus goes through, all the mags will alarm down at the flloor just from the metal rolling past underneath them.

So, yes, whether passengers alarm or not is determined by a combination of two factors: 1) how much metal is on or in you; and 2) whatever happens to be parked, or driving, beneath you.

The alternate checkpoint was added as an afterthought ... it's on the 3rd floor, and the floors are chock-full of rebar, which I believe makes the mags more sensitive. Hand-wanding is also a pain, as everyone alarms from the knees down, thanks to the metal in the floor.