my key with the remote on it spent the winter outside after falling out of my pocket then going through the snow blower and finding it in the spring melt in a puddle going though freeze and thaw cycles.
Had no issues with it an works fine

 

I went on a canoe trip with my 12 year old son and left my keys in the Jeep. I had them in the back under a section of carpet that I could reach from a partaly unzipped window, but you could not see them and would have to know where they were to find them.
It was a good thing, coz we capsized.

 

One of my keys got a severe cleaning in my jean's pocket in the wash machine. I opened the snap cover, rinsed everything and put it and the battery in the window for some sun time. Works fine, now a bit softer from the fabric rinse.

 

Q: How do you know it's a kayaker's Jeep?

A: Shake it and the keys fall out.

 

I haven't taken apart this key yet, but the one for my wife's minivan & her Lexus were both gasketed to protect from water. I wouldn't scuba with them.