Answer : co-incidence or rather obvious planning.
Discussion:
Suppose you were designing an area to filter physical content (things & stuff) on it's way to airplanes, in direct opposition to the intentions of potentially violent non-law abiding people.
Imagine a box directly next to your area in which at any time these potentially violent non-law abiding people could deposit substances or things which may (after a pre configured delay) instantly scatter the content of your area (things & stuff & people) all over the tarmac.
You would have to plan not only for potentially frequent rebuilding of this area (which would admittedly facilitate later improvements), but also for frequent hiring of replacement employees. This can be expensive, and might make your planning appear insufficient.
OR
You could request that the airport move the scary box to another location in the airport. This is comparatively free.
There are additional concerns which involve other sorts of intentional hazards. There is the additional concern of increased foot traffic near what is supposedly a secured area (both user access of owner maintenance). My expectation is that either cost or coincidence is the single driving factor.