It can happen - I was reading on one of the US forums about a chap who hydrolocked his Mazda 6 with a cold air intake whilst driving through a deep puddle whilst turning a corner. He didn't see it as it was late at night.
Ideally - if you are going into puddles deep enough to suck up water, you shouldn't be there in the first place. The problem is - sometimes this sort of stuff happens by accident during storms, etc. Roads in some areas get flooded quickly - deep potholes can be disguised - and you are caught by surprise.
I prefer the K&N to the INJEN as it has a drycharger - sure that doesn't prevent hydrolock but it does something.
This quote is from the Injen web site. http://www.injen.com/faq.html
Will water enter my engine if I install a cold air intake?No, although water can enter the engine if the filter becomes submerged in water. Rain splashes and small puddles generally do not cause hydrolock. If the filter becomes submerged in water it could cause hydrolock and cause damage to the engine. We do not recommend driving through deep puddles and or floods. Most filters lie 12-14 inches above the ground. You may add a device to prevent hydrolock but cutting the intake system for installation will void our manufacturers warranty.
