I am on the "fence" about this article. It seems within the capabilities of a 15 year old to press a button when a referee shouts a word. The responsibility is great when the controversy hits, however.
That's exactly the issue, though - there are a handful of mechanisms in place to ensure that the clock stops and points are awarded properly - electrical equipment is used, buttons on the tips of the Epees are tested with a 750g weight, fencers test on eachother's masks before each match, testing kits are used to check wiring, etc., and the judges are there to watch movements to account for possible disputes. The task of starting the clock has been significantly overlooked compared to the task of stopping it.
Aside from this, the rules and the scheduling of matches are done with the assumption that there will be no major disputes, which needlessly compounds the damage from any dispute that happens.
To have this level of precision I imagine the judge's "allez" would have to be replaced with a racetrack style countdown and green. Otherwise attempting to detect when a specific spoken word has been said (either predicting it just started, or detecting that it has finished) sounds like a complex problem.
When we're talking about hundreds of milliseconds, though, I begin to have doubts.