There was an article in Maclean's some time ago that said that they didn't think that particular machine was particularly effective. They said:
“We’re always looking at new procedures to ensure security”.... Last spring, the agency ran a six-week pilot test of bomb-sniffing machines at Pearson similar to the ones used in other high-profile buildings. They puff air as a person walks through the archway and then analyze the particles for explosive matter. The machines were rejected, says Larocque, because “the maintenance and reliability of the units were not good.”
Is this a debate that's going on in airport security? Are we using the body screener right now because it's the most reliable?