Cutting hydraulic lines before the engine is started guarantees a hydraulic fluid gusher that would be easily discerned before takeoff - it would take just a few seconds to gush ALL aircraft hydraulic fluid onto the runway - it works at 3000 psi.
All thrust reversers are manufactured and fitted with a system of locks and feedback mechanisms. Lock failures show up on the cockpit instruments, and having a red light on will prevent the flight from occurring. The feedback mechanism detects a thrust reverser starting to deploy, and then sends the hydraulic fluid to stow the reverser before it can deploy. If they can't fix the T/R system on the ground, then they put a pin in the reverser structure to prevent commanded or uncommanded deployment.
After the Air Lauda crash in Thailand, caused by a T/R inadvertently deploying, all aircraft makers had to declare their aircraft either reliable or controllable. The big twins like the A300 are not controllable with a T/R deployed, so they had to go the reliability route and install a better safety system with 3 redundant locks. There was a deadline to do it, which has passed, I think. Therefore, it's highly likely that this aircraft had the redundant system installed.
The author is correct that an in-flight T/R deployment would cause the aircraft to fly approximately the way it did. It was the first comment in my office after the crash - it may be a T/R deployment. But the statements from the NTSB make it clear that the T/R's were not the cause.
I've previously offered two probable causes to this crash - a rudder partially breaking loose from the vertical tail, causing high static and dynamic loads before it departs the aircraft; or a latent structural defect in the vertical tail skins that was excited by either the wake turbulence or anomalous rudder operations.
As I've stated before, I am an aerospace engineer at a company that makes engine nacelles, including thrust reversers.