Now THAT I can follow. I'm going to guess that there may have been other indicators that were unreported or missed.
Something binary, fast acting, but not TOTALLY debilitating.
Something to chew on.
The new "group grope" method of smuggling a device onto an airliner could certainly employ a binary technique. There are many things that could be carried aboard that are harmless when taken individually. There are probably things that are not harmless that are not on the screening list. A plastic bottle of liquid can be left in the pockets of your pants and never set off the magnetometer.