Here is what the extremely reliable Wiki says about the issue:
Hydrolock most commonly occurs in automobiles when driving through floods, either where the water is above the level of the air intake or the vehicle's speed is excessive, creating a tall bow wave. A vehicle fitted with a cold air intake mounted low on the vehicle will be especially vulnerable to hydrolocking when being driven through standing water or heavy precipitation. Engine coolant entering the cylinders through various means (such as a blown head gasket) is another common cause. Excessive fuel entering (flooding) one or more cylinders in liquid form due to or other abnormal operating conditions can also cause hydrolock.
Seems pretty consistent with other sites as well. Soooo...if you decide to buy the VF or ESS SC kit, then find yourself in the middle of a flood....well....then you're an idiot, and you should have bought a boat instead.