That would be the 0.1% then.
To the OP,
There are recognised Spill Hazard Zones within some (all?) aircraft. This was incorporated in standard practices after a certain incident as described above caused multiple systems failures. I think it was a B737.
If there is a significant water spillage in this zone then an inspection of the electrical equipment compartments is required before the next flight.
The electronic/electrical racks are protected by sealed floor panels, drains around the door thresholds (on some anyway) and drip trays above the racks. so long as the integrity of these protections is maintained then any spillage should cause no adverse effects.
And therein lies the problem. Maintenance is expensive, lack of maintenance more so.
