got back from Disney a couple weeks back.. the amphicars they have there as water taxis are awesome! you actually get to load up on land, drive down the ramp and off ya go!
but yeah... we get hydro-locked cars in every year. don't try to go through... and if you do, slow and steady. had a truck get it, and the customer was complaining that the water wasn't even that high... turns out he was trying to make huge splashes and going through the middle of it at high speeds... that sends water all over... including up and into the air intake.