Stop and think - thousands of baggage handlers, cargo agents, caterers, fuelers, and other ground personnel generally are not required pass through security (X-ray/metal detectors) - and they have direct access to aircraft.

Why would gate agents pose any greater risk? If some employee is trying to get an item on airplane, there are far easier ways to do it airside vs. landside. The gate agent scenario at MCI is a non-issue. There is a lot more risk elsewhere.