Surfer62 said..
Been using the padlock style for a few years now since stashed keys (wheel arches, bumpers etc ) were getting stolen from cars here. It started to get a bit of salt air corrosion and I've been meaning to lube it, yesterday returned to van after a four hour session and the padlock just wouldn't open, release button jammed, borrowed a screw driver and had it open in less than two minutes, bit surprised thought it would be harder to force open Might pay the extra bucks and get the in hitch style posted above.
I have a similar experience with these, used one on my camper van for a short time in the UK, had it about 3 months and came in from a surf, middle of winter, freezing, going dark. Hands were numb and I got some sand had got into the combination wheels so they wouldn't turn, couldn't open it. Picked up a small stone that I had parked near and tapped it, the thing popped open and I got my key (the keysafe no longer worked after this).
Now I have resorted to the old school techniques- stash a key (away from vehicle if car park is busy), or keep a key tethered to me while in the water.