Via John Aziz of Azizonomics blog,
Interconnected networks exhibit a knife-edge, or tipping point, property. Within a certain range, connections serve as a shock-absorber. The system acts as a mutual insurance device with disturbances dispersed and dissipated. But beyond a certain range, the system can tip the wrong side of the knife-edge. Interconnections serve as shock-ampliers, not dampeners, as losses cascade. The system acts not as a mutual insurance device but as a mutual incendiary device.
A mutual incendiary device sounds about right.