Are key fobs water tight?

With all the new cars having keyless entry I was always wondering what would happen if it fell in to a puddle of water,I mean fully submersed.I just finished an E 300 when are reached into my apron for the key fob and the damn thing slipped out of my hand and fell into my mop bucket.Not even a split second I reached into that filthy water and grabbed that damn thing.So I dry it off and while examining the thing I notice that Benz may have designed this key fob water tight.THANK GOD.I hear these keys can be upwards of 4 or 5 bills with programming.Other key fobs may have been damaged from the water, I sure do not want to find out.

I dropped a brand new Audi fob straight down a drain when i reached to answer the phone . Having removed the drain cover i got it back out with an extendable magnet about 5 minutes later and it worked fine, Thank Phuck, these things arn't cheap !

sounds like AUDI keys are tight. As far as Benz goes...we lost keys in snow banks and found them after the thaw...worked just fine.