I'd say the vast quantities of people running around with AEM CAIs and the relatively nonexistant amount of people with hydrolocked engines is plenty of evidence that it's not a big deal. It's not like if you drive in the rain, or through a puddle, or whatever, you're going to kill your motor. A little water ain't gonna hurt it, because it evaporates pretty much as soon as it hits the motor.

Hyrdolock is caused because liquids are not compressible like gasses are. To cause damage through hydrolock you need to get enough liquid in one cylinder to fill up its combustion chamber. An LS head's combustion chambers are 45 cc, or about an ounce and a half. Basically up to this point you will create higher and higher cylinder pressures which may or may not break something. If you get more water inside a cylinder than the volume of its combustion chamber, the engine will stop. When this happens, something breaks: a rod, piston, whatever.

Now to put that in perspective, that means the engine would need to suck enough water through the filter, up that long pipe, to fill one cylinder with over 45 cc of water. That won't gonna happen from driving over some puddles or in the rain.