One body, after a successful, problem free shoot just crapped out when the second shoot started. It displayed error 80 and the shutter would not fire, the back LCD screen did not display, and the focus/meter did not work. Batteries and CF cards were changed, as were lenses. On the second on pulled as the backup, there was no error 80 but the symptoms were pracitcally identical. The shutter/aperture small screen functioned, but the shutter would not fire. Batteries, CF cards, lenses were all swapped. What gives?
Electromagnetic interference, maybe? If the cameras were subjected to, say, a strong magnetic field between the two shoots, it might have screwed up their embedded processors. Did the second shoot take place near an operating cyclotron or some other such device?