Re: SImpler solution?
Fair point on hydration, definitely but coffee is not necessarily the right choice there (awaiting a study on the comparative electrical damage characteristics of tap water vs. Mineral water vs. Coffee - with/without sugar!).
However, given the degree of risk analysis and mitigation in civil aviation, (e.g. crews timing out due to flying duty hours restrictions, systems redundancy, pilots sober) i am surprised that a more robust solution has not been attempted, as it’s a fairly easy one to mitigate (although maybe introducing the hydration risk you mention).
Pilots will of course never do this on purpose, as I imagine even an incident that does not zap the controls will (ironically) lead to a meeting with the Chief Pilot with neither tea/coffee nor biccies.
Biting the hand that feeds IT
