PJ2
...and we know of the Lauda Air B767 accident which was apparently a FADEC fault. Most fleet types have an emergency drill (memorized...) for reverse deployment in the air. The drill usually involves appropriate rudder input, (foot/rudder pedal in the kitchen and then some), ensuring directional control, and shutting the engine down. FADEC-controlled engine designs on the Airbus (CFM56 installations and likely others) command IDLE thrust if a reverser-deployed signal is sensed in the air.
The FADEC sic (Full Authority Digital Engine Control) controls the engine not the aircraft and its reverser system. The FADEC does use inputs from the aircraft systems and in the event of an uncommanded deployment in-flight it will command the engine to be reduced in thrust to flight idle. Unfortunately, in the case of Lauda etal. the aircraft upset occurred before the engine could fully spool down.
In order for the Lauda reverser to deploy it needed to have a malfunctioning stow/deploy valve as well as weight on wheels (two degrees of protection failed).
All reverser designs had a degree of suceptibility as incident data has confirmed
Newer designs now require a third degree of protection (a positive mechanical lock).