stehsegler said..
Just be careful where you do it. I have had my van stolen at Botany Bay a few years ago. Apparently the crocks watched me from a distances. As soon as I went out onto the water the walked up, grabbed the key and drove off. Someone even watched them... by the time he got up to run over and stop them they were already gone.
Got the van back a couple of weeks later when it was found at a break in at a motorbike dealer. All my gear was gone and the van had about $5k worth of damage done to it. Haven't left my key "hidden" since.
Thanks for sharing that story. I have a friend that thinks its perfectly fine to place the key 'under a tree' instead of carrying it with him. I figure that's fine if its only his gear in the van, but when its mine as well, I'm not taking any chances.
I always carry an aquapac for the keys and the GPS, but sometimes I feel like everyone else is crazy and/or incredibly lucky.