I wasn't hanging off a cliff, but I did walk through knee-deep seawater with 1-2' waves crashing, 7D and Sigma 8-16 around my neck (and held up above my head) to get some cool shots at Phillip Island a few weeks ago.
Camera was fine, it was only when I got back to the car I realised that my phone and car keys were in my (now saturated) shorts pockets.